I’ve qualified as real estate professional since 2021 and just found a potentially good opportunity to acquire a property in Mexico that would make for either a solid STR and/or eventually our forever home.I’m completely new to acquiring a foreign property- how to finance, what purchase process looks like, how foreign STR is taxed, does real estate professional status matter, etc. 

Even if you create a non-CA LLC, if you are managing the business from California, you will likely be deemed to be "doing business" in California and therefore likely subject to CA taxes.

But property tax rates can be lower if you purchase properties in this area located in Wise County.

I have received a refund for a transaction that occurred in the previous tax year.Specifically, this transaction occurred in May 2023, but I received the refund for that amount in January 2024.

They formed all of my entities, prepared my trust and handle my taxes for me. 

Wondering if it's is more tax advantageous to use an S-Corp or a straight LLC for doing my flipping in?

If you got the permits and they are recorded with the county tax assessor, you can list them on the MLS, Zillow, etc as a five-bed with ADU! 

We live in Los Angeles, both are self employed 1099 independent contractors, combined annual income roughly 250k pre-tax.

DSCR also does not look at your income i.e. taxes, W-2, paystubs, etc but rather will look at the potential cashflow of the property. 

You could still get the tax deductions...rents will likely go up, interest rates will likely stay flat or decrease slightly, Austin has a great outlook long-term.