About Ochako, she may be the one who will make arise the heroes who have already left. Of course it could be something about Deku, but I actually believe that she will be the one who will save the heroes. I don't know about Hawks but I'm looking forward to what he does.
Shouji, well based on what Hori says I don't think he will be the traitor.
Shinsou will obviously do something great, there is no point putting him in the hero course now if he doesn't do anything. His quirk is Op if you don't know him or don't know he is there. If there is someone who doesn't get affected by his quirk that would be AFO, Shigaraki and maybe some special rare cases.
Monoma, hmm... I don't know, his character can go to several ways. 1 of them would be him being the traitor. Another would be him, doing something as a hero, maybe Vlad is the traitor and he captures him.
Sero... Tbh to me, he is going to be the traitor. He has been called to be just a 'normal' person throught all the series, if the traitor wasn't Denki or some random teacher then I had clear it would be him, I could be wrong tho but I think his epic scene will be him revealing he is the traitor... Hey like Kanjuurou...
Deku, Bakugou and Todoroki were not mentioned because they are big roles already, same as Endeavor(tho Hori mentioned Hawks).
I wonder more about some characters like Kirishima, Momo, Mineta, the Kirishima from class B, Mirio, Fatgum, etc.