Laramie, I read the three articles.
Fr. Meagher was also Doctor of Divinity, awarded such by Pope Leo XIII (the only American to receive the honor). St. Pope Pius X granted him a private chapel in Long Island City. He was also, maybe not ironically, a relative of T.F. Meagher, a Brigadier General in the Union Army.
The Church has sanctioned slavery at times, but not recently. For the slave class in the Jew West, the Industrial Revolution made slavery inessential, so I'm a bit skeptical of the claim that evolving moral goodness is the reason it was discontinued.
Pope Paul III is known for Sublimis Deus, but he sanctioned slavery afterwards.
Popes issued papal grants to enslave enemies of Christians. St. Thomas Aquinas writes that it's permissible to enslave Jews.
For the Pope Pius IX and Martin affair you could have just quoted my post, as I haven't seen anyone else notice this contradiction in my research. In fact it's the only post in the thread that's exhibited new research into the question.
The figures you quote don't have the best pedigree:
Bar Hebræus (Syrian) was a Monophysite and was also the son of a Jewish physician. -- http://www.newadvent.org/cathen/02294a.htm
Ibn al-Tayyib (Arab) was a Nestorian.
Ishodad of Merv (Syrian) was a Nestorian.
Eutychius (Egyptian Arab), according to New Advent:
"The author states that he has compiled his history only from the Bible and reliable authorities. It contains, however, a great number of strange and improbable additions to Biblical and profane history not found in any other source." --http://www.newadvent.org/cathen/05639a.htm
St. Ephraem the Syrian is an exception. He was declared a Doctor of the Church in 1920, so that gives his teaching more weight.
The first quote from St. Jerome doesn't mention the Curse of Ham, though it suggests it by claiming those with black skin have wicked souls. The quote that does mention the curse doesn't mention blacks.
What I do know is that a Catholic can maintain that the Curse of Ham applies to blacks and not be excommunicated, and can even be made a Doctor of the Church, a Doctor of Divinity and a Pope! So it seems it's one of those subjects on which the Church allows different interpretations.
Slavery and the Catholic Church by John Maxwell (published in 1975) is probably worth reading. I've read pieces of it, but should go through it.
It's also worth reading the Secret Relationship Between Blacks and Jews.