Bettas have a strong preference for being alone, and tend to be agressive to other fish. I think that you would do much better to keep one male in a separate tank then attempt one female and one male in your tank.
You should actually never mix male and female bettas in a tank; they will fight each other, or possible even kill each other. The species is hardwired to fight other bettas. They do get along for brief periods while mating, however, this is a long, careful process and the fish must be separated afterwords. Unless you want some 300 babies - veiltails, which are hard to place - I wouldn't try breeding.
As for the compatibility of a male or female with your other fish, I couldn't say for sure, but females tend to be slightly less agressive than males (not always though). If you want more than one female, you'll need 5 (some people say three works, but 5 is the generally accepted number). That might make your tank a little crowded, depending on how large your other fish are at maturity.
If you choose to try bettas, remember: one male OR one female OR five females, never any combination of male and female
And always have a back-up tank if the betta starts attacking your other fishies (for one betta, something around 2.5 gallons should be fine, for the group of 5 females, 10 gal is suggested)
Hope that helped ^^