Yes, the Whitehorse Walmart continues to host RVers year-round.
There was a bit of a tussle in late 2013 regarding the handful of full-timers parked there, with generators and yard gear surrounding their homes. I believe the Walmart announced they were no longer allowing fulltime living on the parking lot. I suspect one of the issues was the space was required for snow storage when the lot is cleared of snow. There are some good sledding hills popping up in various parking lots throughout Whitehorse this winter.
Canadian Tire does not allow RVers to park overnight on its lot, which is much smaller and shared with numerous stores at the strip mall next door.
I also noticed during the September migration southward that it was sometimes difficult to get a regular parking space to go shopping at the Walmart. The RVers were camped throughout the parking lot and taking up to four spots for a single RV. Often had to weave through and around the camping gear scattered here and there. It was somewhat frustrating.