Innocent III Denies the Immaculate Conception (with more complete citation/sources)

William Albrecht, relying on a secondary source, alleged that the sermons of Innocent III that were quoted in "How Many Popes does it Take to Deny the Immaculate Conception?" (link) were inauthentic.  His quotation stated:

"John Baptist Posa [t] say those sermons of Innocent III were plucked from apocryphal libraries. Fr. Peter of Alva, and Theophilus Raynaudus say that the sermons were by John Lotharius, a Canon regular."

Oddly enough Lothario dei Conti was Innocent III's name before he became pope.  

The sections of the relevant sermons are found among the authentic writings of Innocent III, in the Migne Latin Patrology,  second series, Tome CCXVII.

The Sermon on the Purification of the Virgin is Sermon XII (of the Sermones De Tempore series), and the relevant material is at col. 506-07:

But forthwith [upon the Angel’s words, ‘The Holy Ghost shall come upon thee’] the Holy Ghost came upon her. He had before come into her, when, in her mother’s womb, He cleansed her soul from original sin; but now too He came upon her to cleanse her flesh from the ‘fomes’ of sin, that she might be altogether without spot or wrinkle. That tyrant then of the flesh, the sickness of nature, the ‘fomes’ of sin, as I think, He altogether extinguished, that henceforth any motion from the law of sin should not be able to arise in her members.

Sermon on the Assumption, Sermon 2 (aka Second Discourse on the Assumption) is Sermon XXVIII (of the Sermones de Sanctis series) at column 581.  Note the Editor's note that excuses Innocent III's views on the grounds that the doctrine had not yet been defined.

Eve was produced without sin, but she brought forth in sin; Mary was produced in sin, but she brought forth without sin.

The Sermon On the Feast of John the Baptist, is Sermon XVI (of the Sermones de Festis series) and the material is at column 531.

Of John the Angel does not speak of the conception but of the birth. But of Jesus he predicts alike the Birth and the Conception. For to Zechariah the father it is predicted, ‘Thy wife shall bear thee a son, and thou shalt call his name John,’ but to Mary the mother it is predicted, ‘Behold, thou shalt conceive in thy womb and bear a Son, and shalt call His Name Jesus.’ For John was conceived in fault, but Christ Alone was conceived without fault. But each was born in grace, and therefore the Nativity of each is celebrated, but the Conception of Christ Alone is celebrated.

And you will see from the column range that these are all within the range of the authentic sermons, not in the "Dubiorum" group.

So, I cannot help but think that Mr. Albrecht has made a serious error in relying on the less than reliable pen of Mr. Peter D'Alva (or Peter of Alva), one of the major proponents of the immaculate conception in the 1600s.  Migne's patrology was published, unless I am mistaken, in the 1800s, although sometimes building on the work of preceding centuries.  Nevertheless, between someone with an obvious axe to grind and the Migne patrology, it seems clear who is more reliable.