However, HOAs can also be a double edged sword with fees, restrictions on rentals, or even special assessments.For flips, condos might have less upside since you can’t control the overall property value like you can with a single family home.

First step is always to cut the water source and fix the leak asap.

It may be time to cut your losses and move on from this real estate. 

It would be nice if you had a contact who was an actual mason not a marketer.  1930's construction is rare so maybe they cut some corners it was a global depression.  

If not, cut it all out and put down some strong sturdy plywood.

Cut rates until it rents.

Focus on the big moves: security, renovations, and cutting dead weight. 

My thought is to BRRRR it and refinance, and they get their cut of the equity (which I assume would be split 2:1:1).

Perhaps you start a side business or go all out on cutting expenses that are sacrificing things that you want.

Heavy cases of clear cut fraud and flat out lying to their investors.