I’m about to be 29 and I’m hoping this really takes effect in my life in my 40’s.

Plus for its high cash flow potential, utilizing a 1031 exchange to reinvest gains effectively made this experiment a relatively low risk for me.

Being abroad adds risk to your file and terms will be effected in some way or another.  

I haven't seen any statistics to this effect and I don't think any has necessarily been compiled but I bet I wouldn't exaggerate if I state that 95% of the value of real estate in Southern Spain or at least the province of Andalucia is in the Costa del Sol.

They're often high quality and cost-effective.

Whatever I do, I would need to do with a HELOC—effectively financing 100% of the property (down payment and closing financed with HELOC, rest of purchase financed with a mortgage). 

Yep for one especially in the early stages a hard credit pull would not be useful, just have them do soft checks for the time being and opt out of credit solicitation: www.optoutprescreen.com I could be biased... that said typically working with one lender than can help regardless of where you're looking and having a relationship with that will provide the easiest and most cost effective route long term. 

The effect of this process is that the portfolio is constantly improving by retaining the best properties and jetison the under performers.I've bought and sold over 1,000 properties, and people always ask me "How many doors?" 

I never had that come into effect on my single family home purchases since I never wanted to personally be on the hook for such a high mortgage, but I think it might come into play for an MFH. 

Hi @NA*I am not affiliated with Sodt Pull Solutions*To perform soft credit pulls on potential borrowers, services like Soft Pull Solutions can be highly effective.