School break in AB is that week for public schools. Nakiska may just be a little crowded as everyone around bought a seasons pass, but it is the most popular place to carve (wide open, consistent pitch terrain).
Sunshine is more 'natural' terrain...funner for freeriding but you can find good carving runs. Best snow IMHO.
Lousie is a fun place to carve, I find. Snow not as nice.
Haven't been to Marmot in years so can't comment...
In the past few years our most wet months have been feb and march (in southern alberta)...I'm personally hoping we start getting some good dumps in feb...Dec and Jan have been pretty dry.