your orientation is determined by who you are attracted to & who you date not your language style ergo - really does not matter what you call them as long as they don't mind
Not hardly. "Guys" tends to be a catch all for addressing a group of people anymore. It can be used to indicated a group of males or just to indicate a group in general. I've always used "guys" when talking to a group. i.e "Hey guys."
Only if you make love to them well your doing it. It doesn't even sound like an odd thing to say. (It would seem a tad odd to see a guy call his guy friends girls.)