Custody

My neighbor was sentenced to a couple years in prison for a felony. He asked me to take custody of his dog. I had him sign a release of ownership stating the dog's name, his name, and that he was releasing all interest in her. He recently contacted me and said he was coming home in a few months and wants her back. I love her, she's extremely attached to me, and I intend to keep her. Does he have any rights? I have the release, the nearly two years of her being licensed in my name, a vet visit, and I intend to change her microchip info from his name to mine. Can he take her back?

I adopted a puppy from a rescue. I paid $200 and signed an adoption agreement. They tried to pick up my dog with the police. I refused, and they said it was a breach of contract because I decided to take my dog to my sister's house for a few days to house sit. They were concerned about my dog, but no where in my agreement does it say I can't take my dog where I want to. I had permission from my vet, my sisters dogs were vaccinated, and I was very careful. The puppy is in very good health. The foundation is taking me to small claims court stating that I am indebted to them for $200 and/or I'm not entitled to the dog. Do they have any chance of getting the dog back? I can provide all vet records, vaccinations, and patient notes showing where the vet gave me permission to take him out of state with me. I have personal references of what a great home the dog has. I am worried.

My boyfriend has a retired service dog and a kitten that we got together but was meant for him. I have paid vet bills for both the pets, but they are under my boyfriend's name. If we were to part ways, could I fight for custody of both of them?