suzanne
At the end of the day, it sounds like you really love your cats and are trying to the the best for them. I'm in a similar boat - my cats pee (everywhere!) for many complex reasons and I'm tackling the reasons one at a time - it's gradually getting better now. I personally prefer to use a combination of Feliway and Bach rescue remedies to help them calm down, but that's my choice and it's partly because my cats are really cr@p at taking tablets and also I'd have to treat all 3, which I can't afford.
We've solved the problem of other cats coming in by getting a small dog who runs out through the cat flap and shouts a lot at trespassers- we wanted one anyway and the cats love having her around now. She even intervenes when the cats fight among themselves, which is really really cute!
I could never rehome my particular cats just because they pee, but that's partly because I'm confident that the psychology behnd it is solvable without going that far - and I don't think anyone can make a judgement on the behaviour of other people's cats without meeting them and seeing them in the flesh. I personally prefer not to use drugs but I know it can help and that it doesn't have to be a long term thing, so I wish you all the best and hope Storm settles down soon.
Finally - Please don't stay away just because some people have different opinions to you. That's what forums are all about, it's good to have a debate about these things and it gives more inexperienced people a chance to see all sides of the argument. There will always be people who disagree but at least on Purrs they do it fairly politely and respectfully without the name-calling that I've seen elsewhere.