In both cases to keep things clean for underwriting at the bank I used my HELOC to secure the mortgage. 

Securing financing upfront is paramount.

It isn't having paid off properties that offers security, there are still taxes, insurance, maintenance and management involved. 

But we are also both very used to corporate and used to having a security of a job.

The law does NOT apply to landlords:With less then 5 rental unitsThat live in one unit of a duplex and rent out the other unitThat rent out rooms in the home they occupySo, landlords can no longer state in their rental ads, "Section 8 not accepted".The reverse is also true, "Section 8 only", cannot be used.We've always recommended screening S8 tenants the same way as cash-paying tenants.Landlords waiving application fees and/or security deposits only for S8 prospects may also be violating Fair Housing.

Private lenders or even creating a small syndicate with a group of investors might also be worth exploring, especially since you can point to your uncle’s track record and your own experience managing rentals as a selling point.If timing is tight, you could look into a bridge loan to secure the property while figuring out a more permanent solution.

Exterior security cameras.

They didn’t completely destroy the house, I did keep most of their security deposit and used it for the repairs, along with some of our own cash.

My strategy would then be to lease at least two of the renovated units, increasing occupancy to 90%, which could improve the chances of securing favorable terms for refinancing.I haven't pitched it to the seller yet.

A mix of short- and long-term strategies could hedge against market shifts.Borrowing allows you to scale faster, especially if you can secure favorable terms.