I think you'd be able to accomplish (most?) of what you want to do by enabling the associations feature.
I'm not sure exactly how the association playoffs work though, I've never used them.
If doing a shared draft you'd want to disable draft pick signing, the tiny teams would be drafting players they could never afford. I would also disable pick trading and free agent compensation, they both caused me issues in v24.
Wouldn't take you very long to set up a scale model of your league for testing, make four 4-team leagues with no minors, a 3 game regular season schedule, then see what happens. Sim times would be super quick.
