If it is technically my primary residence, would this be legal even if I rarely actually spend a night there?

Due to the inherent characteristic of this type of siding to deteriorate if not properly maintained and the difficulty in detecting all damaged areas, a qualified siding installer should perform a more in-depth evaluation.

Neither is innocent and I’ve told them both multiple times that they need to act like adults and be respectful of the other (music and noise to a minimum during the day and nothing at night as stated in the leases.)

Then, you must budget properly, sometimes without the benefit of having a full idea of what may be lurking behind those walls.

As far as I know, it's still illegal under federal law to house a growing operation without proper licensing and the funding of one.

@Melanie KentWhat is your analysis on this dealLet’s see the numbers and margins....Cash flow - cash on cash return - Net Income - expenses - I mean these are basic numbers that if presented properly - may provide some incentive for other folks to collaborate a deal.

If you get the "stay" and the property is under court order, the court may require that the proceeds be placed in the registry of the court until proper ownership can be determined.

I looked for middle class neighborhoods that I would be comfortable with me & my wife walking outside at night.

If you keep your day job or can start earning conventional real estate commission income and do the work yourself on nights and weekends, this is a great opportunity to build for the future. 

It helps to make the paperwork more clear by setting up an LLC for the partnership and using the proper loan documents (lawyer can help with all that).