@mdrecht , generally agreeing with your conclusions and suggesting that (a) read the linked page -->The Costs and Taxes of Selling Property in Mexico (mexperience.com) as a starting point , (b) consult a local NOTARIO ( they interpret the law, do all the paperwork for a transfer and each town has a number of these legal people based on the population size) before and during any transaction of real property.
My wife ( a mexican citizen ) has properties in MX and so I am slightly familiar with the process. You DO NOT need to have a realestate agent , if you can find your own buyer but you do need a tax id.
