Where do I start... So. I think the character models are alright with exception to the wolf which I feel could use some work. Though I noticed pretty quickly once I unlocked the cat that the human model has trouble loading in and sometimes comes in bald for a split second. I think It's strange that doing the same position gives half exp. I feel like for a level system the girls should have some sort of preference or grade toward certain types of activities they can improve on. Like the human has a better time with titfucks than the others while the cat is not so good with blowjobs but good with a handjob and the wolf is really good in doggystyle yet average everywhere else.
The way I see it, I think this could be an interesting sort of clicker rpg where you can improve the activities of the women by training them in one of two ways: serving customers or practice and study to a certain extent based on their key characteristics. Training on customers gives more exp but risks lowering reputation of the brothel. Meanwhile practice requires the right item and study material to better understand the activity but it does not generate revenue and reputation while taking much longer to improve. With one extra drawback that certain positions and activities would require a practice partner like for a nursing handjob for example. With certain services being unlocked the higher level prostitute becomes in their respective skills. Like a handjob can be upgraded to a nursing handjob for example after enough time doing it and titjobs.
The core of the game being to become a reputable establishment and getting rich. Starting off small with the choice of protagonist having two different benefits: A female protagonist can participate with those that are hired for more reputation bonus and help in some activities as a practice partner. A male protagonist can help practice with all available activities with more exp efficiency. But both are in charge of finances ranging from paying the workers to ensuring that everything is clean and operational. Which can be done by either cleaning it up yourself or hiring a janitor to handle the messes. The janitor being the auto-click option that cost money while doing it yourself takes a bit longer with clicks and needing the right cleaning material.
Best of luck, I know once you've figured out where you want to take this it'll be a grand time for sure.