We took our first 5th into Mexico a few years ago - registered to husband - didn't return the permit - and then sold it in Canada. We now have a different 5th, and are returning to Mexico in January ...
Our first 10 year TIP was in one name. We made the mistake of selling one in the US while it still had a TIP in Mexico. Tried and tried, and still haven't managed to cancel the TIP. The new moho is in the other name. Rest assured, we'll figure it out this time. We hope/suspect, that when the first 10 year moho permits start to expire, things will change, and make it easier.