Month old kitten has bulging navel and swollen genitals. This kitten & 2 litter mates were abandoned. I have been bottle feeding kitten formula & rubbing genitals to get them to excrete body fluids.

Bulging navel sounds like a hernia

Have you taken them to a vet or shelter?
That is the logocal choice if you think something is not right, we cannot diagnose illnesses on this site as we cannot physically examine the kitten.

The bulging navel does sound like a hernia as danialnoahsmommy said but whether it needs surgery is up to your vet.