I think multiple first is really hard to do unless you have really distinct voices. I tried it once with the result that I totally changed things up so that the snarky character with the much more distinct voice turned into the protagonist, because he was so much more fun.
I actually find it helpful not to be able to directly look into a character's head by not making them a PoV MC. In a way there's so much more you can do with characters if you're not directly inside their head, so to speak. Of course I like manipulative, secretly evil characters for whom this works quite nicely, but it's definitely been a huge learning experience for me.