Krixwell, you madman. I’m pretty sure you just chose to use ponies to make that Weymouth joke. Oh, and random fact- the term “grimdark” actually originates with Warhammer. “In the grim darkness of the far future, there is only war.”

Pfft! Nah, that one just came to me on the spot. 😛

(Hm, maybe it would’ve been called Weymuzzle Mall?)

The actual reason I chose to use ponies was that I realized how well Cupcakes fits in with these Interludes. We meet a brutally violent, somewhat deranged person who has fun doing what she does, and we get to know this person through a separate POV character.

I had already decided on this by the time I read the last part of Interlude 11c, so I was quite pleased to learn about the female newbie in the Slaughterhouse Nine – it couldn’t have been more perfect for my plans.

(By the way, “you shouldn’t look a gift horse in the mouth” is actually an expression in Equestria, being used as the moral of an episode. Considering the meaning of “gift horse”, that has some dark implications that I’m not sure the writers considered.)

“A few seasons later, we learned that Pinkie Pie canonically does have a secret basement under Sugarcube Corner.” Does that mean the writers might have read that fanfic?

Absolutely. The writers of MLP:FiM are very aware of what goes on in the fandom and regularly make nods to it. Hell, the 100th episode, “Slice of Life”, is basically Canonized Fanon: The Episode, a wild ride that celebrates the fandom and the background ponies it has given so much love to.

And then later on there’s “Fame and Misfortune”, by the same writer, in which the Mane Six publish a book about their adventures and everything they’ve learned in the hopes of helping young ponies learn about friendship, only to have the ponies who read it create uproars for all the wrong reasons – flanderizing Pinkie Pie to the point of laughing at everything she says or does, trying to join Applejack’s family, ripping Twilight’s lessons because Rainbow Dash’s are cooler, generally criticizing everything as if it were fictional (”it’s not believable that you would be friends”)… In the end, nothing was resolved (even after this song), but the Mane Six found out they had genuinely helped a few young ponies, and they were happy with that.

Now if that’s not fandom commentary, I don’t know what is.

Anyway, to bring it back to the original question – Pinkie’s secret basement is used for party planning and doesn’t look anything like the place in Cupcakes, for obvious reasons, but yes, I’m 98% sure it was still a reference.