I had 5 unrelated male cats (I'm down to my last indoor boy), who found me one by one, and I never had an issue introducing a new cat into the household, not even a sick & injured feral who was afraid to leave his "hospital room" for almost a year. They all got along and slept with me on an over-sized recliner, and I never saw a hiss, growl or fight.
Guess I'm just lucky. But then, my outdoor critters get along just fine, too. My semi-feral backyard cats have no problem sharing their food with the raccoons, possums, occasional skunk, and even the darned starlings.
I run a peaceful, if somewhat dilapidated, Eden here, dontcha know! :~)