I don't think Aisling's target needs to be Kindred. I'd venture to say the Beast just wants a bit of come-uppance to someone that the Prince had in their pocket. Even a ghoul or a favoured mortal servant.

I think, while it's not something Aisling could pull off herself, that finding a target like that would be a politics or status roll, maybe? Knowing who is who in the former Prince's retinue?