I know that Thurman has a big ego and big mouth, but I haven't heard him trash talking like this one. I think he is confident specially when he heard that he is the odd favorites is this fight.
I'm sure that Manny is also boiling deep inside, but he doesn't trash talking, well not as big as those other boxers, and would gladly put his fist into action than just saying this and that to the media.
I think it is just part of the promotion, this thrash talking thing. We can't deny the fact that Manny is the first big name in boxing that Thurman would fight and he seems to maximize the moment. What is talking for me is doable though of little percentage and if he can pull off this one he would be the next big name in boxing. This match needs lot of promotions as Manny is on a downhill while Thurman is not popular.
Probably, but they are not force to trash talk their opponent, I never seen Manny doing the trash talk so that only depends on how the boxers feel in the fight. Manny is religious, in fact for those who does not know yet, he is church pastor IIRC, respect the Legend so he will get some respect when he is in the ring.
I saw some fights of Manny before, when he is about to knock down his opponent and he feels he beaten it badly already, he looked at to the refs hoping refs will stop the fight to avoid further damage to his opponent.