Snow has been firm but in good condition because of the colder temps. Pretty much just riding groomers and a few tracks through the trees. Don't expect to be finding powder stashes anywhere close to a normal run. Is it your first time in Whistler because either way you will have a blast.
It hasn't been too busy of late, which will be nice for you. Bare in mind this coming weekend is an American holiday (I think, and if you aren't american) so Friday/Sat/Sun will be a bit busier then it has been. Come Monday though it should be back to normal
The temps in Whistler look like they should stay reasonably low (compared to the locals in Van) so I wouldn't worry to much about that, however the freezing level totally spikes so