Have you found lenders willing to provide this, or are you using alternative sources to bridge the funding gap?

 You may be able to secure higher leverage financing through alternative lenders than a traditional bank (not always the case) and this may help advance your objective of reducing the down payment/cash requirement but that may only be temporary relief as you will likely pay more over the course of the loan because of higher rates and fees.

First off, you should know that getting a loan as a foreigner in Mexico is quite difficult—most traditional lending options aren’t available, so you’ll likely have to explore alternative financing or fund the construction yourself.When it comes to managing the property as a short-term rental, you'll need to decide whether you want to open a small company in Mexico.

Alternatively, you could look into seller financing on the new property, which requires less upfront cash.

Here are my 2 cents (and probably some alternative options/strategies you might consider)...hope this helps. 

But if tenant stability and needing cash flow are higher priorities for you, then it may be worth re-evaluating or looking at alternative properties that offer more reliable cash flow from day one.

San Diego and the surrounding areas are VERY ADU friendly so there are properties with options to add one in the back that are really starting to pop there and could be an alternative option.Take it slow.

Johnhttps://www.biggerpockets.com/blog/why-reits-are-safer-than-...

Portfolio loans, asset-based lenders, and home equity lines of credit are all alternatives to traditional borrowing.

I could alternatively put that down in a index fund for S&P that gets about 8-11%.