Once Starbucks is there you are well behind the curve.Ways we monitor are watching local papers, planning meetings, studies, and one of the best is your local business journal.  

We loved living there so much, and saw such a huge potential in Tulum's happening real estate that we opened our own boutique real estate/ architectural studio, Riviera Maya Property Consultants.

I have 43 properties right now that I'm wholesaling and the way I do it if the spread between the price I'm buying it for is less than $10,000, I just have the buyers sign a Consulting Fee agreement.

Lynette Hellerich, works for RE Consultants.

Like in the example of buying a quad, living in one, rehabbing the rest, increasing rents for the rehabbed unit, using the GMR for the area to find a new valuation price for the quad, refinancing, buying another unit, waiting for another year, monitoring the GMR and selling the first unit at a high appreciation, using the proceeds towards a 1031 exchange and repeating the process.

You might have to hire a lawyer, and/or a CPA, and/or a tax consultant to advise you on the best way to go.  

For example, I've seen contracts drawn up where an individual is acting as a "consultant" and  advising/assisting the seller who is selling their property FSBO by advertising it, where at that point I can fully see where "acting as a broker" could be the accusation. 

With regards on how to handle the tenant situation - you need to consult a lawyer.

If you're investing with friends, I would just have a very clear, in writing and signed(maybe even want to consult an attorney) agreement as to who owns what and who is responsible for what agreement.  

I currently live and work full time in Tokyo Japan for a recruitment consulting firm and have only recently started researching about real estate investment.