A 10 gallon is a bit too small for Corys...I wouldn't recommend getting any less then four, six or more being ideal. And a 10 just doesn't have enough room for them, unless they're pygmies.
I wouldn't suggest Tetras either, a proper school along with the females would be pushing it in a 10.
I highly suggest you pick up a couple more females. All may seen fine now, but that can change in the blink of an eye. Better safe then sorry....and this means you can go betta shopping ;)