I manage my parents rental portfolio which consists of 1 mobile home park (20 units), and about 15 other houses.

A friend's parent?

Keep in mind that all this time we were living with my parents paying them rent but saving/starving to score our next deal. 

I was able to move out of my parents house in an expensive market by using the other unit rent to cover the majority of the expenses.

The parents owe roughly $40k on the mortgage. 5.

I think their logic was that a family with 12 people (parents and 10 boy children) would have difficulty finding a suitable house with say 6 bedrooms.In addition to the Federal guideline, some local ordinances address occupants both tenants and owners. 

Filing the parent LLC was easy,  $400 to the state this time, everything online approved within a few days, but then I went to file my first series for a property. 

As a parent, and landlord, and previous renter I will always choose to live or rent in the area with the higher rated schools - maybe they aren’t Blue Ribbon Schools, but a C+ rated Elementary School > F Elementary School.

For a place like that a sleeper sofa would be appropriate if there are kids traveling with parents, but IMO even 2 bedroom units would have 1 bedroom go unused most of the time. 

I previously owned a long-term rental that I bought from a parent and rented to family for over three years (lesson learned!).