As promised, here's more insight into the Marian devotion Blessed John Henry Newman developed as a Catholic, starting with his defense of the doctrine of her Immaculate Conception:
Two years after the proclamation of the dogma of the Immaculate Conception, Reverend Doctor E.B. Pusey wrote a public letter to the other great survivor of Newman's "defection" from the Oxford Movement and the Church of England, John Keble: An Eirenicon, responding to then Archdeacon Henry Manning's public letter to Pusey, The Workings of the Holy Spirit in the Church of England", in which Manning denied that the Church of England was protected from error the way the Catholic Church is. Pusey mentions the recently proclaimed doctrine of the Immaculate Conception of the Blessed Virgin Mary (declared by Pope Pius IX in 1854: "We declare, pronounce and define that the doctrine which holds that the Blessed Virgin Mary, at the first instant of her conception, by a singular privilege and grace of the Omnipotent God, in virtue of the merits of Jesus Christ, the Saviour of mankind, was preserved immaculate from all stain of original sin, has been revealed by God, and therefore should firmly and constantly be believed by all the faithful.") and examines it in a historical context.
She holds, as the Fathers teach us, that office in our restoration which Eve held in our fall:—now, in the first place, what were Eve's endowments to enable her to enter upon her trial? She could not have stood against the wiles of the devil, though she was innocent and sinless, without the grant of a large grace. And this she had;—a heavenly gift, which was over and above and additional to that nature of hers, which she received from Adam, a gift which had been given to Adam also before her, at the very time (as it is commonly held) of his original formation. This is Anglican doctrine, as well as Catholic; it is the doctrine of Bishop Bull. He has written a dissertation on the point. He speaks of the doctrine which "many of the Schoolmen affirm, that Adam was created in grace, that is, received a principle of grace and divine life from his very creation, or in the moment of the infusion of his soul; of which," he says, "for my own part I have little doubt." Again, he says, "It is abundantly manifest from the many testimonies alleged, that the ancient doctors of the Church did, with a general consent, acknowledge, that our first parents in the state of integrity, had in them something more than nature, that is, were endowed with the divine principle of the Spirit, in order to a supernatural felicity."
Now, taking this for granted, because I know that you and those who agree with you maintain it as well as we do, I ask you, have you any intention to deny that Mary was as fully endowed as Eve? is it any violent inference, that she, who was to co-operate in the redemption of the world, at least was not less endowed with power from on high, than she who, given as a help-mate to her husband, did in the event but cooperate with him for its ruin? If Eve was raised above human nature by that indwelling moral gift which we call grace, is it rash to say that Mary had even a greater grace? And this consideration gives significance to the Angel's salutation of her as "full of grace,"—an interpretation of the original word which is undoubtedly the right one, as soon as we resist the common Protestant assumption that grace is a mere external approbation or acceptance, answering to the word "favour," whereas it is, as the Fathers teach, a real inward condition or superadded quality of soul. And if Eve had this supernatural inward gift given her from the first moment of her personal existence, is it possible to deny that Mary too had this gift from the very first moment of her personal existence? I do not know how to resist this inference:—well, this is simply and literally the doctrine of the Immaculate Conception. I say the doctrine of the Immaculate Conception is in its substance this, and nothing more or less than this (putting aside the question of degrees of grace); and it really does seem to me bound up in the doctrine of the Fathers, that Mary is the second Eve.
It is indeed to me a most strange phenomenon that so many learned and devout men stumble at this doctrine; and I can only account for it by supposing that in matter of fact they do not know what we mean by the Immaculate Conception; and your Volume (may I say it?) bears out my suspicion. It is a great consolation to have reason for thinking so,—reason for believing that in some sort the persons in question are in the position of those great Saints in former times, who are said to have hesitated about the doctrine, when they would not have hesitated at all, if the word "Conception" had been clearly explained in that sense in which now it is universally received. I do not see how any one who holds with Bull the Catholic doctrine of the supernatural endowments of our first parents, has fair reason for doubting our doctrine about the Blessed Virgin. It has no reference whatever to her parents, but simply to her own person; it does but affirm that, together with the nature which she inherited from her parents, that is, her own nature, she had a superadded fulness of grace, and that from the first moment of her existence. Suppose Eve had stood the trial, and not lost her first grace; and suppose she had eventually had children, those children from the first moment of their existence would, through divine bounty, have received the same privilege that she had ever had; that is, as she was taken from Adam's side, in a garment, so to say, of grace, so they in turn would have received what may be called an immaculate conception. They would have then been conceived in grace, as in fact they are conceived in sin. What is there difficult in this doctrine? What is there unnatural? Mary may be called, as it were, a daughter of Eve unfallen. You believe with us that St. John Baptist had grace given to him three months before his birth, at the time that the Blessed Virgin visited his mother. He accordingly was not immaculately conceived, because he was alive before grace came to him; but our Lady's case only differs from his in this respect, that to her the grace of God came, not three months merely before her birth, but from the first moment of her being, as it had been given to Eve.
But it may be said, How does this enable us to say that she was conceived without original sin? If Anglicans knew what we mean by original sin, they would not ask the question. Our doctrine of original sin is not the same as the Protestant doctrine. "Original sin," with us, cannot be called sin, in the mere ordinary sense of the word "sin;" it is a term denoting Adam's sin as transferred to us, or the state to which Adam's sin reduces his children; but by Protestants it seems to be understood as sin, in much the same sense as actual sin. We, with the Fathers, think of it as something negative, Protestants as something positive. Protestants hold that it is a disease, a radical change of nature, an active poison internally corrupting the soul, infecting its primary elements, and disorganizing it; and they fancy that we ascribe a different nature from ours to the Blessed Virgin, different from that of her parents, and from that of fallen Adam. We hold nothing of the kind; we consider that in Adam she died, as others; that she was included, together with the whole race, in Adam's sentence; that she incurred his debt, as we do; but that, for the sake of Him who was to redeem her and us upon the Cross, to her the debt was remitted by anticipation, on her the sentence was not carried out, except indeed as regards her natural death, for she died when her time came, as others [Note 5]. All this we teach, but we deny that she had original sin; for by original sin we mean, as I have already said, something negative, viz., this only, the deprivation of that supernatural unmerited grace which Adam and Eve had on their first formation,—deprivation and the consequences of deprivation. Mary could not merit, any more than they, the restoration of that grace; but it was restored to her by God's free bounty, from the very first moment of her existence, and thereby, in fact, she never came under the original curse, which consisted in the loss of it. And she had this special privilege, in order to fit her to become the Mother of her and our Redeemer, to fit her mentally, spiritually for it; so that, by the aid of the first grace, she might so grow in grace, that, when the Angel came and her Lord was at hand, she might be "full of grace," prepared as far as a creature could be prepared, to receive Him into her bosom.
Regarding Newman's devotion to the Blessed Virgin Mary, remember that he included praying the Rosary everyday in his short guide to perfection:
If you ask me what you are to do in order to be perfect, I say, first—Do not lie in bed beyond the due time of rising; give your first thoughts to God; make a good visit to the Blessed Sacrament; say the Angelus devoutly; eat and drink to God’s glory; say the Rosary well; be recollected; keep out bad thoughts; make your evening meditation well; examine yourself daily; go to bed in good time, and you are already perfect.
He also wrote a series of "Meditations on the Litany of Loreto" for the month of May, dividing the titles of Mary in that litany according to her Immaculate Conception, the Annunciation, her Dolours or Sorrows, and her Assumption. In a "Short Service for Rosary Sunday" Newman demonstrated his love for the Blessed Virgin Mary:
IN Jesus Christ is the fullness of the Godhead with all its infinite sanctity. In Mary is reflected the sanctity of Jesus, as by His grace it could be found in a creature.
Mary, as the pattern both of maidenhood and maternity, has exalted woman’s state and nature, and made the Christian virgin and the Christian mother understand the sacredness of their duties in the sight of God.
Her very image is as a book in which we may read at a glance the mystery of the Incarnation, and the mercy of the Redemption; and withal her own gracious perfections also, who was made by her Divine Son the very type of humility, gentleness, fortitude, purity, patience, love.
What Christian mother can look upon her image and not be moved to pray for gentleness, watchfulness, and obedience like Mary’s? What Christian maiden can look upon her without praying for the gifts of simplicity, modesty, purity, recollection, gentleness such as hers?
Who can repeat her very name without finding in it a music which goes to the heart, and brings before him thoughts of God and Jesus Christ, and heaven above, and fills him with the desire of those graces by which heaven is gained?
Hail then, great Mother of God, Queen of Saints, Royal Lady clothed with the sun and crowned with the stars of heaven, whom all generations have called and shall call blessed. We will take our part in praising thee in our own time and place with all the redeemed of our Lord, and will exalt thee in the full assembly of the saints and glorify thee in the Heavenly Jerusalem.