Mark 8 opens with the story of a miraculous feeding, and while the SAB suggests this is the result of "two oral traditions of the same story" just as in Matthew, there is a moment (in this Gospel in verses 8:19-20) where Jesus refers to the two feedings as two clearly separate events, so I don't think so.
I responded to the question of signs and wonders in Matthew 12.
The SAB asks two questions about Jesus healing a blind man, "Where did Jesus cure the blind man?" and "How did Jesus cure the blind man?" Frankly, I think the two stories are so different that there's no contradiction, there's just two completely different blind men.
I know I've already answered the charge somewhere that "There were various opinions about the identity of Jesus...With credulity like that just about anyone could later be passed off as the risen Christ." but it's worth addressing again. In one case, you have a bunch of people who are trying to figure out who Jesus is from rumor and speculation; in the other you have a specific claim about a specific person that nobody seems to be willing to question. It's food for thought, but I don't find it convincing.
I'm also sure I addressed the question of whether Jesus forewarned his apostles, but the response is simple enough to give again: just because John says they didn't understand doesn't mean they weren't told.
Yes, when Peter was acting adversarial, Jesus called him "Satan" which means "adversary".