You'll likely want to evaluate the investment with UDFI tax figured in.The Solo 401k trust would make the payments to the seller/lender and would also pay for any investment-related expenses.

It couldn’t be coincidence that he finally started work, the day after I asked for the lockbox code.

I'm a local real estate broker, investor, and manager (100+ rentals, mostly Airbnb/STR and multifamily).House hacking is a tried-and-true method and in Sacramento you can produce some meaningful income while enjoying the appreciation and tax benefits of owning real estate.

So you are able to get the cash flow, tax deductions, etc.

After closing, when the property taxes were due I never received any bill.

This might make sense, but again, you are just deferring the taxes and now pushing tax from capital gains to ordinary income. 

Pretty much think of a commercial loan process as a residential loan process backwards.Lenders do go off the income of the property, but they also do check out the purchaser...3 years tax returns and a personal financial statement. 

The houses would be looking at I'd imagine would be about 7 to 800 k taxes would be about 4K hire a year.

We have sold (tax free), kept as long term and/or short term rentals as well.

Find out if they owe any back taxes.