Huh, now that was an interesting compare/contrast of the vampire and satori sisters.

Hmm, given their previous works, I'd say this is still Remilia X Reimu, but I'm too lazy to do anything more aggressive than comment on it.

Im really liking this pairing

they have a pretty interesting dynamic

The Satori and the Scarlet are really a nice pairing. They really look alike, Satori x Remilia both have similar problems and can understand each other.
Koishi x Flandre they complete each other. They are pretty similar and the official work showed that the Scarlet and the Komeiji have deep friendly relationship.