If your room is at 66 in the day and 56 at night then that averages out to 61. If you are swinging your temp back & forth like that you definitely want to insulate your carboy to keep your yeast happy. You can also figure that fermentation is going to raise your beer temperature above room temp by maybe 5 degrees. That being said, I don't think you have to worry too much about which ale strain you use. Something like WY1056, WY1028, or WY1272 from WYeast or 002 or 007 from White Labs should do OK. If it takes a few extra days in the primary that's no big deal, you'll just get a cleaner beer. You could certainly go with a Kolsch, Alt, or Scottish Ale yeast, but I don't think it's really necessary.