/g/474582/5f08632276/ the Yuuka part appears to be based off of this. It's interesting how he styled Yuuka after the cosplayer some though the Yuuka in this is cuter/slightly bustier compared to the cosplayer.
Pretty nice and the Parsee part is a nice extra, not sure if that's based off of anything, though the page Reimu(PC-98)/Meira yuri (by Booch) was very surprising. Though I do sort of wish the Yuuka part was longer.