So I'd like a bit of help with how/what to do with a few pokes on my team.

First off, I'm working on a set of Trick Room pokemon just because, top of the list being Cofagrius. I'm wondering who would be good to go with trick room. Multiple pokemon in general, I'd pick the ones I like most out of them, but I have no idea where to start.

Second, I got my 6IV Mawile, adamant/intimidate, and got its atk EV's maxed, but don't know where to go from there. It's already slow as fuck so should i desperately try to raise its speed or should i increase it's bulk a bit?