I wouldn't feel up her belly, that's probably a good way to damage the babies. Hard to tell when she will pop, some stay pretty small, mine once they reach "golfball" stage usually give birth within a few days. Is the other female pregnant as well? It's best to have them cycling and having babies together, otherwise they may kill the younger litter. They may kill this litter, some aren't great the first time around.
Don't mess with them for at least a few days after birth, just add food and water and spot clean as needed. Food sounds fine, male should be fine, however he will try to breed the female babies too young so you may want to separate them out at 4 weeks. Male babies same deal, they will breed mom or sisters at 4 weeks and also will start fighting amongst themselves, I feed off males first.