If your angels are new to the tank, it may take them a little bit to get used to things. When I add new fish it takes a couple of days for them to coming up with the other fish to feed. If they get hungry they will get in on the action.
As for the sex of the angels. I'm not an expert on this, but I think it is a little hard to tell until they start to mature. I think I have two females in my tank, but I'm interested to see what other responses you get on this.
In regards to the fry, I wouldn't worry about taking the mollies out of the tank if you dont want to keep the babies. You may actually help solve your first question