There are GP rescue centres. Considering they live 7 years and a lot of people grow bored with them b4 that's up, it would be very kind of you to try to get one from rescue.
BUT, from a rescue centre, you may have trouble finding a pair that will live happily together, and they are seldom happy living alone. Also, rescue animals are more likely to have health problems.
Vet bills are far far below what you'd get for cat or dog.
They need hay or grass everyday, plus a source of Vitamin C -- they can die without those things. They shouldn't have celery (too stringy) or rhubarb (poisonous).
Ours lived outdoors, but you must keep them protected from drafts and wet. We had them in wire mesh-surrounded runs outdoors during daytime hours (still need somewhere inside the run to shelter from wind and rain). They will keep your lawn mowed, if you like (mustn't use garden pesticides any more, though).
Ours were never happy runningaround indoors. They leave concentrated staining wee and are just too shy for it. but somehow they should get out of cage and run around daily for at least 20 minutes (on average).
They probably wouldn't go near anybody, much less a baby. The odds of them biting or hurting anybody are virtually nil.
hth.