Validate planning zoning requirements and access to utilities.  

But it’s awesome that you’ve got a plan and are ready to make it happen!

Where I am looking for guidance is we plan on using a larger down payment of at least 50% to be on the conservative side of leverage.

However, for a primary, especially if you plan to be there a while then it may be worth the hassle.

What I'm most concerned about is the Project 2025 plan to gut HUD and most social services.

The basics of a seller financed deal are that the title co or closing attorney (if there is one) or seller’s attorney draws up the warranty deed transfers title, the promissory note evidencing the debt related to the transaction, and either the deed of trust or mortgage (whichever is being used) perfecting the lien against the subject property.  

Either1) your startup takes off and you can distribute profit fast enough to pay off your debts, or2) you find another source of $100,000 a year (which barely even starts to pay down the $300k, but might provide a better chance for a better loan), or3) you BK and possibly lose the rental houses to creditors (hopefully not, but we don’t know how they are held), or 4) you sell the houses, take the tax hit, work with the IRS on a payment plan whose interest will be much lower than your CCs, and focus on the startup.  

I plan for a time when they can be there and check in and make sure there aren't any maintenance items they haven't told me about.

However it is important to remember to make sure you have a plan to pay that loan down and not allow that credit card debt to climb back up.

Looks to me there isn't a lot of room for creativity in SLC based on my understanding of Zoning and Planning.