http://whitewolf.wikia.com/wiki/Clan_(VTM)

Personally, I'd see Twilight as a Tremere, Rainbow as a Brujah, Pinkie as a non ugly Nosferatu (Mostly cause she can basically dissapear and reappear whenever), or a Malkavian. Rarity is OBVIOUSLY a Toreador...

Twilight - Tremere
Applejack - Giovanni
Rainbow Dash - Brujah
Fluttershy - Gangrel/Tzimisce
Rarity - Toreador
Pinkie Pie - Malkavian
Sunset Shimmer - Tremere/Baali
Starlight Glimmer - Ventrue/Tremere
Trixie Lulamoon - Ravnos

6486996
Starlight would be part of the Anarch Movement and or Independent Clans.

6487079
Hmm, that makes some sense

6487004
All good.

6486996
6487004

Rarity is OBVIOUSLY a Toreador...

Is it obvius, though?

Since day one, Rarity's whole deal been how she longs to be refined, and part of high-society. Heck, she's even got that Mid-Atlantic Accent, and you HAVE to train to get one of those.

But, well, she's got the karate. She'll complain up a storm, but if needed she's one of the first girls to get her hooves dirty. She even does commission work for a living, something that gels rather poorly with the Toreador's flaw of creative sterility.

Honestly, I'd personally peg her as either Brujah, or even as one of the few, rare Nosferatu that aren't physically deformed slash have mastered flesh-sculpting.

(The girl does have a ton of make-up on at all times, and spends more time maintaining her beauty then the rest of the girls COMBINED, after all.)

I remember a clown that was very based on like purity and humanity and that seemed like that maybe that might fit Fluttershy.

Rarity could also be a followers of set or the Assassin.

I guess it meanly depends on which Edition you're thinking about when you're considering these also some of the Clans are from the live action role playing Mind's Eye Theatre group.

6487297
Assamite.

6487260
Hmm, good point, its just her eye for beauty reminds me of a Toreador, or a wannabe Ventrue.

6486996
The Klan. I heard what they said about Mules.