The tenant has been paying significantly lower rent for quite some time, approximately $200-300 below market price for a similar unit.

At higher properties you need to use a lower %, and this is driven by your market.

What happens if: the rehab costs more than expected, the flip is delayed or the sales price is lower than expected?

Commercial transactions are liabilities by comparison.

I have focused on minimizing my expenses so that my "financial freedom" number is lower. 

By having your own license, you will need to be under a Broker who will charge you something for this (some charge a flat fee per deal, some charge a flat fee per month, but most charge a % of the transaction (AKA split).

This type of transaction happens all the time in the commercial world.If this has been helpful, please vote for this post.

The larger the transaction, the more thorough the vetting process will be.  

Account ClosedMark is referring to the prohibited transaction rules which would absolutely prevent you from putting an asset you currently own into your IRA or 401k.You can invest a self-directed IRA or 401k into real estate, but as a disqualified person, you would not be able to transact with your retirement account.

The second loan would be a 30-year fixed lower interest asset-based non-recourse loan.