Well his entire point of being right now is to be the Harry Potter-style red herring. With the Philosopher Stone being on the show (that's what Alchemy is using, as we saw in the previous episode), the actor's clear reference to the franchise, and his overly blatant antagonism to the hero is right up there with how Snape was portrayed, particularly in the first movie/book.
It is being overdone, but I think it's actually intentional. At least on the writer's end. They're trying way too hard to convince everyone he's Alchemy.
I never even considered that he could be Alchemy until you said that. Now that I think about it, I can see him being a red herring, but for some reason I just never got the vibe that he could be Alchemy. Plus, he actually gave Barry the clue that Alchemy was behind Magenta's powers this episode, and there really isn't a reason I can see for Alchemy to do that. Still,its an interesting idea, but it feels unlikely.