There actually is a Devil Survivor 2 anime and it's awful.
Honestly they can work the major mini games once you get out of midgar into episodes and character moments. Like a chocobo racing episode where someone overcomes a fear of the creatures? SureFinal Fantasy 7 Rebirth. Yes please!!! It could be so cool with a FF7 series but I think it maybe should be a own story like Fallout. Otherwise only the Midgar portion is fitting for a series.
The fun thing is that the world feeling in Fallout isn't that far off from FF7 though. There is old tecnology mixed with futuristic mixed with fantasy. And they uses many cool elements that remember me of FF7 world and lore (I have played Fallout 3, New Vegas and a couple of hours of Fallout 4).
With that said it probably won't be happening. Everything about the world lore, story, concepts and everything is great in Fallout but much better in FF7, but I doubt it will be translated as good in to tv. Advent Children is probably enough.