You also need to consider that at a lower percentage of money down you will be paying a Mortgage Insurance Premium or MIP. 

Hey @Justin Brown, what @John Underwood said is spot on.SLC has been restricting STRs for a long while now and it isn't going to get better.People who have STRs in areas where they are not allowed are breaking the law and will eventually pay the price.Having said that, you should check and see if there are certain areas where it is allowed in some way and that is why they exist there.

Get them to give you an idea of what they are paying for party /event space now in Amarillo and if they would sell your venue for you.

Depending on how close I was to having 20% equity in the property and being able to avoid PMI, I’d consider using some of my cash to pay down the mortgage when I refinanced.

I obviously want to pay the lowest taxes over time.

Next up I'll be exploring what would the seller pay for peace of mind?

This wasn’t a required expense.Property Taxes - $926.88We put in the offer to pay the full years property taxes vs. split them at the time of the sale.

She does not own the lot and pays like $150 per month lot rent.

Property damage, excessive wear and tear, but paying, that PM has an incentive to look the other way, don't they. 

That way you can take advantage of the tenants paying down your mortgage and the appreciation of the property .Best of Luck.