They are the Amazoness Quartet. They are a part of the Dead Moon Circus. Their names are CereCere(the pink haired one), PallaPalla (The blue haired one), JunJun(the green haired one), and VesVes(the red haired one).

Their Sailor names are Sailor Vesta, Sailor Pallas, Sailor Ceres, Sailor Juno.

I hope that helps!