Also any that become friendly and I can catch I will get into a rescue or shelter.
This concerns me... if you've caught them, I hope you mean for TNR (trap, neuter, return), unless they are a stray cat that has willingly walked right up to you the moment you met it, meaning it's indiscriminately friendly to everyone.
You care for the cats, so it's important to note that a cat that may become friendly to you, their caretaker, is a world different than being an adoptable cat. It likely is going to revert to being feral around other people and that is a death sentence at a shelter. The cat would likely not even make it to the adoption room for the general public.
I've been taming a semi-feral in the garage the last few months and he's starting to get to the point where I finally don't feel like I need
oven mitts/leather gloves around him - but I'm still not taking that risk; he's super friendly, but if there's even a slight chance that I think he may still bite it isn't worth the risk. Cat bites are very serious.
To take Jasper as an example: He wants attention like he's starved for it, but that isn't good enough to have a cat adopted. Yesterday when an essential stranger poked around in the garage Jasper hissed a few times and growled menacingly at them. I haven't heard either from Jasper in quite some time... but I wouldn't have put it past Jasper to bite them if they'd tried getting in his space. He went up to his bed (top of a fridge), but them came back down to sit on me with a very watchful eye on the stranger. That type of that behavior around an unknown person is not going to get a cat adopted. Magnify that by the beyond stressful environment at a shelter, and you realise that the cats are better on the street.
About your water dish problem: You mention all the empty homes, I'm going to guess they've been empty for a long time and no one is moving to the area? Any chance you can leave a door open (I'm thinking a sliding door) in one with the water inside? That might prevent it from freezing.