Or you can hire an engineer and have them write letters explaining quality of work, materials used etc to verify that the work was done correctly. 

This is what I put in several "white letters." 

Would a seller be enticed to sell to a non-cash buyer with a SLIGHTLY higher offer and pre-approval letter?

The big reason is that I treat my tenants professionally without throwing emotion into the mix and ramping them up, I document everything, I know the law, and I have policies and procedures in place to act quickly when trouble arises.Now that I've bragged about it, I'll probably have an eviction soon and ruin my record!

But Eagle Scout mixed with "Girlfriend" tells me young.

I have written all of my congressional representatives about these poorly thought-out provisions of the CARES Act (and I'm happy to share a draft of that letter with anyone who wants to do the same), and NARPM, the NAA, and other organizations are actively lobbying for improvements in the legislation. 

@Ronald Rohde SBA won't do residential or mixed use (unless incidental to operation of business).

If you add that factor into the mix it becomes a difficult sale.  

Typically you can obtain a letter from a HML.

One of the biggest risks of investing via SDIRA is breaking the firewall between the SDIRA and you - committing a prohibited transaction, mixing funds, providing your SDIRA a service, other things like that.Buying a property on your own makes that very difficult.