For starters, I suggest you tune in to the BiggerPockets Podcast and connect with the local lenders and brokers.

The rate quoted was 8.875% so I really want to stay close to that as well.

Where do you guys suggest I start?

The cookie-cutter projects in Tulum have had lower occupancy rates due to various factors.

As mentioned, your taxes will be higher than the number they gave you as homesteads are taxed at a lower rate and you’re not living there.

lower the size of your unit and therefore your build cost per unit, your sale price will go down but focus on density and get familiar with zoning and what your city will approve. my best suggestion is to do it in downtown districts where there is unlimited height and unlimited floor area and you can build every square inch of the property and reduce parking because of proximity to transit. property values are higher, rents are higher in downtown markets, there are just too many economies of scale compared to suburban deals.

Look on Airbnb and see what the competitors calendars, nightly rate, and amenities look like, and it should give you a pretty good idea what the numbers would look like for that home. 

What’s the interest rate?

Pretty much any market right now is going to seem overpriced when you look at price to rent ratios and it's a rocky time to start flipping with rates doubling in a couple months.

As others have commented - DSCR Loans tend to be a great solution for people in your exact scenario - fed up and tired of giant hassle and paperwork for conventional or bank financing - not worth the often pretty small benefit in rate or terms.Check out this article I published last year on BiggerPockets on what to expect documentation wise for DSCR Loans - they have become a nice blend between solid underwriting and doc sets needed, but not too much (and not too little like notorious "no doc" loans)https://www.biggerpockets.com/blog/what-documents-do-you-nee...