(Part 1 here)
Shortly after getting my visa sorted out at the Boston Consulate, I headed for Mexico!
On the flight to the Cancun airport, I completed an FMM on the plane. I used "Otro/Other" as the purpose of the trip (you do NOT want to enter the country as a tourist at this point). I also went ahead and checked the "Canje" box in the part of the form reserved for the use of the Immigration officer (it is vitally important that this be checked). I was not asked any questions about the "other" purpose of the visit or about having checked off "Canje" when I presented the FMM. The immigration officer fretted over my documents for a bit then disappeared with my passport and FMM for a while before returning everything to me filled out and with "Permanente" written on both parts of the FMM (which later my facilitator said she hadn't seen before).
Later that day, I met with the facilitator with whom I'd been working via email until that point. This is the primary step at which my experience will diverge significantly from that of someone doing this on their own.
She had me sign an application, a letter (written on my behalf in Spanish) saying how much I love the natural beauty and community of Cozumel, etc. to explain my desire to live there, and a power-of-attorney to allow her to submit documents on my behalf. She had my wife sign a letter saying I live at our house in Cozumel since the house and utility bills are in her name - a letter from a landlord would work as well. An address in Mexico is a required part of the application and any changes in the future must be communicated to INM in a timely manner. Renters are welcome, but a hotel naturally won't work. I gave her the departure portion of my FMM after scanning it.
I provided her with a stack of "infantil"-sized color photos. These really should be done on the island since the photographers know the requirements. Those include frontal and right-side views showing the ears, without glasses, not smiling, and wearing a collared shirt in front of a white background. We used Avenida Foto Estudio on the western side of 30a Av near Calle 5 Sur nestled between Compucentro and Fu-Lin restaurant. I never would have noticed it if two people hadn't specifically recommended them and told me exactly where it was (then it was obvious where it was...). More photos than I will need were 100 pesos. I look like a thug in them, which appears to be the proper result.
Because I had to return to the US before the process is complete, I had to get a Permiso de Viaje allowing me to leave and re-enter Mexico. This took 3 days and one of the photos. I'm told they are never available more than a day before one's planned departure and usually take 3 business days to get.
I had to take my Permiso de Viaje to the INM office at the airport, where I filled out a new FMM and got that properly stamped and signed. The departure portion of the Permiso de Viaje was stamped and the *arrival* portion of the FMM was stapled to it (the departure portion was kept). I will need to present the Permiso de Viaje to the Immigration officer when I return, have the arrival portion stamped, and submit it to the INM office in Cozumel within 10 days of my return. I think I'll also need to do a new FMM, but plan to clarify this before I return.
Note that at no point have I yet been to the INM office in Cozumel and my application is being processed! It's now been a week since everything was submitted and I have not been notified of any requests for anything additional.
Now I wait for everything to process through the system. Once it's burbled back to the top, I'm told the next step is to go in for fingerprints and a brief interview accompanied by my facilitator as translator, which will be my first trip to the INM office. At some point, fees will have to be paid. Most people will do this by going to a (any) bank, handing them cash, then getting a receipt.
The final step will be to go in and pick up my card. It's important never again to enter the country as a tourist after beginning this process, so if I can't wait long enough for my card to arrive from Mexico City I'll need to go through the Permiso de Viaje process again. Some people give someone (such as their facilitator) power-of-attorney to pick up the card and FedEx it to them*. Once the card is issued you must present it to the airport's or border crossing's INM office before leaving the country and will lose your residency status if you fail to do this or enter the country without it, so if it's mailed and lost one must go through a process of getting a replacement card through a consulate that doesn't appeal to me. I suspect I'll probably fly in to pick it up, but FedEx'ing would be considerably cheaper.
*N.B. - although several people on other forums reported having done this, my immigration lawyer said that nobody other than the person named on the card is ever allowed to pick it up, power-of-attorney or not. So don't count on doing this!