Overall, I definitely like this idea, but there seems to be a caveat to one of the points. If your goal is to feed other people chocobo's, then this would likely still not be an option.

What I envision with this suggestion, is we pay a flat rate to 'rent a farm' we talk to an NPC, and we enter an instance, much similar to an inn room. We are alone, but instead of a bed, summoning bell, etc, we have a single garden plot, a single Chocobo Stable, maybe a small hut with a bed etc. (Let's be honest, we have to be fair and give a benefit to the FC's who can and did fork the gil over for these benefits).

It's a rental, so you probably can't do much in the way of modifications to the house. I think for the reality of this project, and what it's intended to address, that the point is moot. If Yoshi's team(s) can add in customizability without impacting the servers much at all, then go for it. If it creates even an additional medium load, I say drop customization as this should be a more light-weight project, only updated/modified based on the player demand/usage. (Once implemented they would be able to get a clearer forecast of it's uses. Some people might never rent preferring to buy, just like IRL)

This has the potential to be a light-weight solution to unlock content for players who are otherwise unable to access it. With that vision in mind, it's a great idea. Some of the finer details to be worked out by Yoshi's team. (Like pricing of rent etc. Really, we know there's a guy who watches the game economics, pricing it out would be his job)