[sweetwater]

My brother is the one who pays the vet bills for an abandoned cat, but the neighborhood considers him a community cat. Everybody loves him and he mooches or smooches without prejudice. If you are a human who might have food or a soft chair in the sun or kids or just want company, he's there. He is even welcomed at one house a couple of doors down even after he discovered their cat's litter box on the 2nd floor. He meows at their door, they let him in, he socializes then trots upstairs, uses the litter box, and then wants out to go visit someone else.
Not sure what the law is where you live, but in some places cats are considered 'semi-domesticated' animals and not subject to licensing. That means a found cat is yours even if someone else raised it, but it works for them if they find 'your' cat, too. Good on you for adopting the kitty, and tolerating the urinating on the floor. I'd try 3 boxes or more because that is not a habit I would encourage. I have 2 boxes for one cat, but she's older and I want her to have every chance to get to the box in time. And I only have to clean every other day, too. btw, you didn't ask for advice, but large storage bins with litter in the bottom make nice big boxes for multiple cats as long as they are agile enough to jump the side. Good luck with the kitties!