Yes. Even with multies and similies, dominant males will harass non-dominant males. However, the cool part, is all the fry are accepted and you end up with a colony of fish. Similies are reported to be more aggressive than multies, but I don't know for sure.
With brevis, once you have fry, I think you need to remove them. (I've never kept brevis)
For a multie tank, you want shells, shells, and more shells. You can't have too many.
Multies are also famous for rearranging the sand, but in a 10 gallon, I think I'd literally cover the bottom with shells, and you can go a few layers deep.