We lived in a very large corporate owned complex prior to buying our house five years ago and the reason we were told we had to leave the complex was because the corporation re-wrote the pet clause of the lease to encompass "dangerous dogs". They also did not specifically name pit bulls.
We argued and fought to have our dogs "grandfathered" into the lease because we had rented for the three years previous to their re-writing the lease -- we may have won, but I'll never know because 9/11 happened and we chose to move closer to the city because of my husband's job.
Anyway, rather than relying on PetCo for her vax, she needs to establish herself at a good vet that can then give her a recommendation. And she needs to be honest about the breed -- lying can get her into a world of trouble if an incident were to ever happen. She could lose her insurance and be personally liable for any damages her dog might cause. If she doesn't have insurance, she needs to get it NOW. That's part of responsible ownership.
I don't think she stands a chance of keeping her apartment -- she signed the lease knowing that
"breeds of dogs known to be vicious" not at all specific but it does allow the umbrella of "breed" not just each dog judged on its own
were not allowed. To go out and get a pit bull or mix thereof was asking for trouble.
Her best bet is to find a privately owned apartment that allows dogs and has an understanding landlord. What town does she live in?
Never make someone a priority in your life when that someone treats you like an option.