Would the potential rental income count towards offsetting the mortgage?  

Short-term vacation rentals involve renting out properties to travelers for short stays, typically through platforms like Airbnb or VRBO.Getting Started: If you're interested in flipping, start by researching local real estate markets, analyzing potential deals, and networking with real estate professionals, contractors, and lenders.

While you are invested in the DST you could potentially earn monthly cash distributions, gain potential appreciation on the property and takie advantage of tax benefits (depreciation).

Do you have every potential renter complete this or only select one renter based off the pre-screening process?

You'll find agents, lenders and other potential teammates there.

--DB A DST or DST to 721 UPREIT is a potential option. 

For the past year I have been looking for a place to buy as an income/airbnb to buy in Mexico and have inquired about Playa del Carmen and Tulum and keep coming back to Tulum as it seems like it has the potential for growth with airport coming and simply more infrastructure.

The new loan at a 5% interest rate would then pay off the seller's remaining balance, effectively transitioning your financing without additional down payment.It's also worth noting that some lenders might allow a "cash-out" refinance, where you could potentially take out more than the existing loan balance, given enough equity in the property, which could be used for further investments or improvements.

@Laura Winegardneri think it will probably be difficult to find a lender that would take into account 'potential' STR income... but even if they did, yes, i think that would be risky. 

@Atlas Blake House Hack a multifamily that has value add potential whether cosmetic fixer and or adding units to it.