Just be sure to operate them properly so as not to pierce your corporate veil. 

If you follow the BRRRR method properly, you can certainly accomplish this.

@James Colgan check out CBIZ or Proper.

I, on the other hand, feel I need a little bit more, like something in writing from that person that says they will not give the code to anyone and that if something is not left locked properly and the house is broken in because of that, then they would be held liable or something of the sort.I remember that there are people who do this, but I don't remember if there is a name or there is an example of said "addendum" for it. 

One has a partial flat roof and the other is all shingles (multilayer but less than 3) If the shingles are curling, bare or missing, just replace it properly.

If the GP's aren't properly compensated, most likely they won't do well.

The proper policy for that would still be a homeowners.  

This opened up the backyard to create a nice outdoor space for tenants (previously the backyard wasn't functional).

Just to give you an accurate expectation for other deals I just sold one of my investors a deal that if executed properly is able to cash flow at 32% CoC very confidently and can be pushed as high as 40% assuming everything goes really well this was in Forest Park.

I'd recommend you add a proper exterior beam and upsize any small pier bases.