Any type of rain pant will work. They need to big enough to layer over some fleece or poly L.J.'s. You do not need to make a fashion statement, you need to stay dry.

Waterproof gaiters.

Snowshoes, well, read the recent thread on shoes. Buy used if you can. Buy quality if you can afford it. Nothing is worse than post holeing your way back to the trail head because a cheap harness broke.

I always bring a piece of closed cell foam to kneel and sit on.