Or maybe have a squatter coming in on a down week and taking over.Or maybe you like dealing with folks sleeping in your back yard or having a derelict RV on the street in front of your house.I am being a bit hyperbolic of course, but our area isn't owner friendly at all and it is getting worse.

It was possible for a resident to view a property, be approved, sign a lease, and move-in without ever talking to or meeting a human affiliated with the owner or property manager.

Do Sellers look at DTI ratio when doing a owner to owner transaction? 

Might be a slight consideration for some owners. 

https://www.irs.gov/newsroom/how-small-business-owners-can-d...

If I wanted to owner-occupy a 5-10 unit apartment building, would I be able to do 5% down conventional financing or must I do the 20% down simply because anything 5+ units is commercial? 

For example in many jurisdictions I can STR units in a duplex but cannot STR an ADU (some jurisdictions will let you STR if you owner occupy).

There is HOA debt in the amount of $21k piled up from previous owner.

Terms can be whatever the owner makes them / you negotiate3.

The owners of the company have 10 acres where they build a few manufactured homes and use those as STRs.