I'm always afraid to keep a collar on my babies in the house because I'm afraid they will get hung up on something or eachother when playing. I know there are harnesses with their contact information embroidered on them. My babies are all microchipped but I never see the vet check to see if it is my dog or not. I recently had my Trixie to the emergency vet and they didn't check her chip to see if she was registered to me. I thought all vets were supposed to check when they have a new patient to make sure the dog is not a lost or stolen dog
Anyway welcome from a fellow Long Islander. I'm with you, I could never just keep a dog that was lost knowing there is a family out there hurting and worrying. I would do everything in my power to make sure they were reunited again. Welcome to YT there are very knowledgeable friendly people here who pretty much have an answer to anything. Good luck with your baby.