On Friday I put our male betta in with 5 neons in our 5 gal hex. At first he would strike at a neon quite often. I kept an eye out during the day, thinking if he didn't settle down I would take him back out as not to stress the neons so much. After a while he settled down a bit. Over Saturday he would chase them just a bit, but not really "strike". Yesterday two of the neons where nosing him and he let them. So I think they will all get along.
This is going to be our QT tank when we get new fish, or a sick fish. I don't want to put him back in a bowl when I need a QT. I am not worried about the neons in the 55g but still not sure about the betta in there with the mollies.