Oops

Well, I suppose this is the risk I run by establishing fan-lore for a show in progress. Of all the world-building elements introduced in the latest episode, there's one that just completely conflicts with the Harmony's Wrath AU: Granny Smith being among the founders of Ponyville, making the town only about 50-70 years old. Now, there are a couple of things I can do with this:

1. Completely rework the entire AU. Not gonna happen.
2. Dismiss Granny Smith as an unreliable narrator. A bit mean, but plausible, and perfectly within my limits having diverged the canons between S1 and 2.
3. Completely ignore that part. A bit lazy, but also viable.

But again, something like this was bound to happen sooner or later.

Comments

[Harvest Puzzle]

I would say go with option #3 because its harder to say someone is wrong because one would have to prove them wrong (which isn't hard considering that your the writer), most stories have some truth to it which means that you would have to pick apart her story and change it as you wished. Also considering that they haven't met Discord yet (until after the death of the celestial sisters) also shows that your story isn't exactly spot on to the show anyways. So i say don't worry about her and carry on.

[DreadedCandiru2]

I would go with Option Three also; after all, you've already established that you're not in Faust's Equestria so you can ignore anything that might get in the way of your fanon.

[SatoshiKyu]

I'm in agreement with those above, option three sounds best in this situation.