I'm sorry, I like this chapter, it's a nice change of pace from all the grimdarkness, but the naming of Rarity throughout this seems inconsistent, which bugs me.
In the first part, (Twilight's POV) she thinks of her as Rarigreed, yet calls her Rarity, but also thinks of her as Rarity sometimes.
(Disregard the following instances if there is anything special about the name changing and I wasn't clever enough to find the reason.)
"Rarigreed wanting to be straight like friends should if we were really going to bring Apple Pie into our circle of friends. Of course Spike agreed with Rarity."
""What?" Rarigreed blinked at her.
AJ citing 'Cleanliness is next to Alicornish' and Rarity looking a mess and not even noticing it?"
"Forgot Rarity wasn't the only one who hadn't had a bath for a thousand years! She may have even been MORE filthy than Rarigreed thanks to the sweat of a thousand years march, and going through whatever it happened to be raining at any given moment Twenty-Four/Seven for the last thousand years, which was rarely water."
The bath scene.
I would find more, but real life calls for me