I’d say that Sherbert is a dark green DF dominant pied (or alternatively recessive pied), with Stella being a grey (or mauve?) greywing with either DF goldenface or DF yellowface II. Sophie looks to be a violet opaline spangle with clearflight pied (however the lighting makes it difficult to determine the number of dark factors), and Kiwi is an olive green opaline.
I’m no expert on the helicopter/feather duster mutation, but it’s definitely possible. :\