If i recall correctly spawning a player with 0 Health, or was it 0 lives in a LMS match the bots totally ignore you. I'm not saying mess with those values I'm saying if you can find where it is in bot section of the gameclass that it checks for above 0 values, and then change that part of the code using a custom game class or mutator, whichever works

you'll probably need more help once you find it, if that didn't help you then theres definitely other ways to do it, just don't make me relive my memories of messing with the teams [EMEMY] values because they are hard coded into the game and are a pain in the ass (adding a 5th team color or multiple team colors that are not enemies (not only red) in monster hunt). I've also messed around with teaming optional team games and the rocket launcher lock-on and it really is a pain in the ass how hardcoded that stuff is

good idea though and i look forward to helping you make it a reality

PS. Monster hunt 2 although buggy apparently allows for more colors than just red and monsters (bots) that don't attack each other. Too bad the author can't take responsibility for his actions, he's retired now so if he didn't obfuscate his code you could try seeing how the ENEMY value between bots is disabled