I manage a couple properties this way, but am under no illusion that it provides any liability benefits.

When using the seller concessions, there is no impact to your rates and the seller pays for your closing costs. 

I'll check out TenantTurner as that sounds interesting, although Avail performs well as my one-stop shop. 

You can put money into no risk 4 week treasury bills right now for over 5% ( technically about 4 when you consider taxes ).

And seeing it was on a no interest credit card I think of it as just borrowing money, not going into bad debt. 

I do trust this partner very much and feel very comfortable that the outcome will be good no matter how the deal runs because of our relationship. 

I know there's the inspection period and buyer must perform due diligence BUT it never is normal to research permits for every single plumbing fixture, electrical box, all liveable areas, etc.

No debt and credit score is around 750.

There are no seasoning options available. 

Allowing a family that large in a basement apartment is no bueno and you probably knew it.Do the basement windows have proper and legal eggress?