They really don't look at all like a Bombay from this distance and angle. I mean they are black but that means nothing at all. Unless they come from a breeder with papers the vast majority of cats in the whole world are just Domestic short or long hair. They aren't like dogs where they can be a mix of this and that. They just simply aren't.
Where did you get them and what makes you think they are Bombay? That is an extremely rare breed.
Black cats are so beautiful! I would describe them as black domestic shorthairs. Most cats are not any particular breed, but that doesn't make them any less special
Bombays have much rounder heads and smaller rounded ears. Your cats look like Domestic Shorthair (DSH) cats. I don't see anything that would make them a specific breed.