I've thrown Banff, especially Sunshine Village, back into the mix. I can keep costs down staying at one of the many hostels and perhaps tag along with other solo travelers / skiers.
My preference is the 4 I mentioned but I see those as scenarios in which I'll be almost guaranteed to be alone for the entire week.
Now for some pure decision-making advice. You've got 5 choices; honestly, how big is the difference likely to be between the best/cheapest and the worst/most expensive? Probably not that much. So, put the 5 names in a hat and pick one. If you don't like that one, pick another. Book it, and spend Saturday and Sunday skiing.