Everything about the 'vert top is the same as a coupe with one exception and that would be the weight of the snow/ice just sitting on it. If having to park it outside is the only option in your case/area, then yes, that would be a concern. But the cold & hot weather extremes testing done to these cars systems to include the top is excellent. But again, the only concern to me would be the weight left to sit on the top if you don't clean it off.
As for the top down and windows up, yes.
http://www.camaro5.com/forums/showthread.php?t=70602