I think you're fine. The yeast may not last as long as it would've had they not warmed up, but they're fine for use in the near future.
You should be find to make a starter with the questionable ones. That is, in fact, the best way to tell if the yeast is good. If it takes off you should be fine to make beer with it.
Yeast is an incredibly hardy thing. I've been told it is the bane of a microbiology lab since, if it gets in, it is positively impossible to get rid of it. Good thing for us, though!