I think the mountains are a little bit too big on the central continent, and like you said they don't match up with tectonics. Perhaps this might serve to give you some ideas, it helped me a lot. When two plates press together they make many mountain ranges that run somewhat in parallel, like the Alps. Maybe you could model the mountains in the central continent on the Alps. The freezing poles I think are just a fact with an earth-like (same tilt) planet. The poles get very cold, since they don't get as much energy from the sun, and freeze, forming a crust of ice.

All in all, looks like a good start to me.