He's the first to use them, and the only one with the backflip if memory serves me right. But if you really want to go there, he's the only one who actually managed to prevent a loved one from getting turned. Yes, boys and girls, I'm talking about Annette.
Game wise, hes the first to use item crash. But Timeline wise, Trevor is the first to use Item Crash. In CoD he has Item Crash. So if you are going to bring that in. Please think on that first.
EDIT: I think I'm wrong there.... Leon might've had it too.Yes, Richter didn't fail. He didn't allow his girl to get turned. Guess what? Trevor wasn't even involved when Syphawas turned into stone, and yet turned her back.
I can't say forsure, because its been a while, but I believe Trevor has the back flip in CoD too. Though I could be confusing my memory, since he does a forward flip when he jumps too.
If you want to judge awesomeness, how about Leon? The only Belmont that can use a whip, not to swing, but grab a horizontal bar, and somehow whip himself upwards without swinging at all. (I'm not a Leon fan btw, his story was so..... cliche and boring imo.)
I think it was actually Maria. In the hentai. 
That was badly drawn btw, Maria was just not "Maria" in that, we allknow she looked much hotter than THAT!