The location being Las Cruces, New Mexico was yet another sucker punch that has negatively impacted my ability to do much with the property.

Getting your real estate license can be helpful, especially if you want direct access to listings, market data, and the ability to save on agent commissions.

I think the ability for the lower cost places in the midwest to 'cash flow' has been way, way overstated.If you know a market well though, that's definitely an advantage.

I'd start by getting a soils engineer to look at the soils around the building to determine what's gone on to cause the heaving or settlement.

Then a Civil Engineer, an Appraiser to determine what having a four unit would be worth, then a loan using the evaluation.

What kind of calculations should I use to determine whether or not this is a good idea?  

What’s the best way to determine if a lender specializes in conventional, commercial, hard money, non-QM, or DSCR loans?

Because they aren't traditional tenants in the sense with a 1 year lease and to determine fit for the house, I like to start everyone on 2-4 month leases and see how they perform.

If your numbers are solid, you might even be able to cover the monthly payments out of the rehab budget.This kind of setup works best for properties that need significant rehab, and you need to be confident in your numbers and your ability to get the work done. 

You can't raise the rents in a fixed term lease but if it's month to month you may have the ability to make a change with notice (30 days is fair in my market).