I have read a number of these early writings on various websites. More often than not I find them to be inconclusive about details unless they're specifically referencing some heretic or event. Often times these writing are very vague. Although they're good for the general thought of the early Christians, people make far too much out of them.
I would say that if Ignatius states Paul and Peter to be in Rome, then there MIGHT have been some truth to it and most likely was. That doesn't confirm anything-certainly not Peter living there for 25 years. He doesn't say that and gives the impression of just the opposite. One father building upon Ignatius writings, which I can read, becomes nothing more than a myth.
I wouldn't idly speculate about the "evils" of early Popes. I think there is enough factual information about some of the later ones to form conclusions. Pope Leo wanted people to kiss his dirty muddy toes, and this is someone who the Catholics feels infallibly made decisions for the Church? Pope Horatio was considered a heretic after he served 16 years and they burned all his writings so what does that say? They ran one Pope (Urbana???) out of the Vatican. For a number of years the Catholics had two (sometimes three) Popes serving in various parts of Europe although they would like to say there has always only been one, even though both were duly elected. And then there is the infamous legend of Pope "Joan" but we won't go there. I'm not impress when the Catholics try to explain to me the pedigree line of Popes.
BTW-I noticed you do not subscribe to "replacement" theology. Christians do not "replace" our Jewish forefathers but we have been grafted in to the heritage of Abraham. This isn't just the teaching of both Catholic and Protestants, this is the teaching of scripture as well. Paul is clear on the fact that we believing Gentiles have been "grafted in" with the Jews. Unbelieving Jews are not children of Abraham. Jewish believers are our forefathers. It is difficult to argue with the plain teaching of scripture written mostly by Jews. If your looking into history, I would suggest you look more objectively into this matter.
I understand this is not scripture, but it is interesting how some things just seem to line up....when we take the blinders off.