The Fuerteventura cat cafes are great. My parents have a time share there. Since they've been going the amount of cats has drastically reduced, which is really good news. They always look out for cats that haven't been spayed and let the Twinkle Trust know where they are. They tried to get a cafe on their site but the committee wouldn't go for it.
The only problem is my Mum fell in love with a young white cat that hadn't been spayed while they were staying there. The Twinkle trust took him in but said he couldn't be released as he was a high risk for cancer. He's now living the life of Riley in Cornwall and my parent's are quite a few hundred pounds worse off.
No doubt where I get my daftness for cats from.
Regarding the London cat cafe, it doesn't sound like the cats are adoptable. I think the cafe will adopt them. It might not be too bad if the cafe not too busy but all the cafes seem so busy and noisy in London.