For brothel there are at least three potential employees in Pavlovsk Natasha, Sonya and Katja Meynold.
Dance Studio could have some story with Albina.
Model agency could have two paths: just modeling or modeling+escort.
I kinda like this idea as well. As long as its also an option for Sveta to also work there. Anushka is probably another good candidate as an employee. She seems open minded enough for the job. Then there is Christina if you go down that questline. Gives you another thing to do with her if you successfully dominate her. Then there is Albina and her crew (see below).
Might work quite well as a mini-brothel sim so to speak. So much you can do with the storyline.
a) Standalone business, with its own storyline.
b) Extension of the Albina storyline (maybe convince her and her girls to continue it as a form of easy money, afterall they have done it before and have experience. But maybe this time with proper facilities and perhaps a bouncer for safety.)
c) Multiple branches (in the City, and Old Town). There could probably be a whole arc on her competitors not being happy about it, or even the mob trying to muscle in and wanting its cut.
d) A corruption mechanic on NPCs could even open up possibilities on other girls working there. Not just those whose current character would suit the place, but rather any girl that is not totally against it could be corrupted by Sveta over time. (E.g Sister, classmates, etc.) IIRC there already exist a storyline where Sveta persuades her sister Anya to pose with her as her twin so that her pimp Pavlin can sell their services to a particular client.