Yes his book is very good, I enjoyed the part about q but I was more interested in everything else.
I think I stated in your other thread that it would make sense for Peter to assume that preaching to all nations and tribes and tongues meant the Jews spread all over the empire. The Jews lived all over. I've always felt Peter likely believed this. However, while he was beckoned to go to Cornelius once he accepted he never questioned again, only his actions showed he needed to be corrected.
Your comment about the body of Christ being one and a house devided is true, and if these people were perfect and unaffected by their culture I would agree the gentile dilemma meant something other than it does. However as it stands, they were a people affected by thousands of years of culture that wouldn't be undone just because suddenly it's okay. It would take time to include Gentiles without anyone wondering about it.
As far as the Mark account, the writer assumed knowledge of birth, death and resurrection was known. One way this is shown is by how the Jews use the phrase," son of Mary" instead of son of Joseph when referring to Jesus. This was a derogatory reference inferring his illegitimacy. It's a direct call out to the virgin birth story.
as to the fighting regarding standardization of the church after constsntine, this is because of the warning given by the apostles. As i stated in the other thread, both Peter and Paul left instruction that after their death only oral and written teachings by them be used and remembered. Yet, after they died sects popped up teaching different things, and other books were created. The Christian movement was standardized already before the apostles died. Afterwards, people introduced their own ideas, in the same fashion as those mentioned by Paul in galations. This destandardized Christianity, resulting in varying beliefs which corrupted the original. Then the worship was further corrupted by the pope via my above posted information.
Summarizing, the real standard is the first century example. Any and all writings or teachings developed by people who weren't of the first century apostles is literally trash. Yet that trash came to define Christianity by the time of constsntine and was expounded on by the Catholic Church.