So.... How exactly do fuschiabloods like feferi come into existence? It's stated that the condesce would kill all heiresses as they pose a threat, so why would she create them? Also, who would she possibly pail with? Even a violetblood (dualscar) could be put to death for liking her. Is it a biological compulsion thing? Is she not immune to the imperial drones?

Well Feferi came by Meteor so the whole process doesn’t really count for her. But its likely that Heiresses pail before Condy comes and kills them supplying the slurry with enough fuchsia-y goodness to pump out another heiress down the line