Lesson I learned was finding a good tenant and getting the prospective tenants fully vetted with their income and debt to make sure they can afford my rent.

It also allows you to grab debt from bank easier since there is more revenue and expenses going through this compiled LLC vs. each individual LLC.

Will this eliminate your chances of being a victim?

You can't compete against the all-inclusives unless you offer complimentary food and booze or you're cheap, as you seem to be confirming.This being said:1) Properties in Mexico/Cancun trade in USD so you have no foreign exchange risk in Mexico while properties in Colombia are traded in COP, the Colombian peso, which has been tanking over the years, eliminating any hope for capital gains for American investors.2) You can get a mortgage in Mexico but you can't in Colombia so even with lower revenue, Cancun would likely still be more profitable, even if you don't take capital gains into account.3) The political risk is much higher in Colombia, especially at this present time.Is Cartagena a bad investment?

Until Fed begins to cut rates I’ve found alternative lenders in some cases to be competitive with banks on construction debt when considering the totality of factors (rate, leverage, depository relationships and pre- payment penalties).

Is it debt way above the 5-6% you can get guaranteed from the bank?

I confirmed that his parents had no debt on the property. 

Every aspect of real estate is syndicated from ATM machines, farms, to multifamily to debt funds. 

And my current DTI is basically zero as I have no outstanding debt or living expenses right now.

Please note though this is an asset on your estate and if you have debts those also need to be resolved/paid which could complicate things - thus why I strongly recommend an estate planning attorney and a real estate attorney.