I've never had trouble with bettas in community tanks. My wife's betta chases the neons around and occasionally picks at the mystery snail, but only enough for him to pop off the side of the tank. No harm done. The betta in my tank will chase the male guppies a little, but there's enough plants to provide cover for everyone to be happy.
Bettas get along with most fish in a community tank. Stay away from fin-nippers, anabantids (gouramis and other fish in the betta family), and any other fish with long flowing fins that might get mistaken for another male betta. (Yes, I know I said I have a few guppies in with my betta, but the male betta is generally too busy showing off for the female to be bothered with them.) Shrimp would probably also get eaten and I think a frog would bother a betta. Snails should all be fine.