That's a problem I have trouble with too.
I have a story that is basically a big crossover fanfiction of live action soaps that I'm calling original. It's a comic format but if I ever want to make money off of it, how do I cover my ass?
One can just say: Well change the character's looks. The Slice of Life/Drama format itself isn't copyrighted.
But it's like the dynamics of the characters themselves are what's staying. In court they could probably just argue that my character is a drawn version/fanart of that character, not a character that shares visual and story similarities.
Only one character being seen as a rip-off would be ok but this is an entire cast.
I'm not even doing it for money/recognition/artistic bankruptcy reasons, I just wanted to write a fanfiction and sucked ass at making them act in character so I created a world around my weird interpretations of the characters.