Hey! What a shiny floof and floomp you have. Three of my cats have come from Lost Dogs, one from Lort Smith, and the others directly from friends/neighbours. Maneki Neko seems pretty decent, a friend has fostered for them in the past. Introducing a new cat I've always chosen the new to be younger than the resident regardless of gender. No power dynamic disasters but ymmv of course. Worst combo were sisters who barely tolerated each other.
I don't wanna!