Or Bloodwish. Which is half of the stalkers. Then again, Galen the Malamar is also purple, and there are purple furs on a Purugly, so Kanna the Purugly is also not exonerated from that list either.

We could always investigate Franny as a first step.

As for the message-Consider the graffiti walls. 'Daddy says not to listen to Yandil.' That message came up in the note from the apartment; that means Daki, Nillian and Drisha are all prime suspects. It wouldn't be the first time a Stalker has attempted to use the slanderous name of another to get their ways.
@Tashy the Furret, can you queue up the Black Feather for your next scan?