I don't know. Don't have a trap, would have to buy one, I guess. Geez, cat drama is making me nuts! I have enough to worry about. At least with dogs you can fence them in, but cats are a special PITA.
ETA: We will take him to the vet tomorrow. His right paw is obviously painful, plus he is really hurting all over, looks like to me.
Ah that stinks! Maybe the vet has one you could borrow! I know what you mean though. Ours used to get out and go all over. This one we don't let out anymore but she used to go out. Our first cat got attacked by a coyote, my dad found him and nursed him back to health, this one brought males to our yard lol we don't live in a rural area so I assumed all were neutered? But it was weird. She never got pregnant despite not being able to spay her right away. Once spayed all the males went away so maybe they weren't neutered haha
Anyway, is there any way you could put something over the fence so Finn can't get loose or other cats can't get in? Like maybe some chicken wire, snow fence, bird netting, or something cheap to put over the openings just he can't run through? Or coyote rollers over the top so he can't jump over? Or is the property too big for that? I'm used to smaller yards so it may not be practical on a bigger area.
That's good you're taking him to the vet though, hopefully he can patch him up! And maybe you could ask him about the fighting and the strays, he may have some advice or ideas on what to do.