@Gregory@Gregory Keleshian It all depends on your objective.

Responding to objections on creative finance, texting sellers. 

The initial objective would be a live in flip. 

I wasn't surprised to receive  tenant objections, but one thing a tenant said got to me: "Just because its legal doesn't mean its fair".This person has lived in the unit 10+ year without any previous capex rent increase.

No system is perfect, so don't waste your time chasing after the next shiny object.

As for plumbing problems and other issues, price overcomes all objections.

I would like to try to track down the previous owner, to get some relatively objective information.

It prevents the usual “try something for a few months and give up and move on to the next shiny object” syndrome.However, I would disagree and say that house hacking is a good start if it works with your family dynamics.

If a neighbor raises a serious complaint you will be forced to stop construction for a while and they can also object during the permitting process which would kill the progress. 

(I'm in your area so I feel your pain on sheetrock cracks. ) I can't imagine the owner would object as you're fixing up his house.