The MC might not get the club shut down though...I suspect and expect that will be down to player choice. But if you think that we're not going have to deal with this stuff coming out before the ending and whatever you choose to do with the club, you're kidding yourself. MC's mom and Mina will almost certainly end up finding out about the club way before the end.
I suspect you're probably right. Ideally I'd like to at least get rid of Chuck and Kat, eliminating the main negative influences.
I'd wondered how the MC would deal with it if/when his mom and Mina found out, since they seem to be the only two people close to him that don't already know. His mom will probably be okay, she will be a little shocked initially, but she loves and trusts him enough to not be mad. Plus he'll likely have to tell her what's going on in an attempt to keep her away from it.
As for Mina, I'm not sure how she'll react. As time goes on she becomes less and less innocent, and after meeting Hana and Felicia, and developing the friendships with them, it might not shock her as much. Time will tell, I suppose.
Personally I suspect the ending choices will come down to change of management or leaving the club. I think MC could help Hana or Felicia replace Kat or side with Kat...something along those lines.
If the change in management meant replacing August, Chuck, and Kat with Hana, Felicia, and the MC, so that they could run the club as they see fit, then that might work.
The club could still be about sex, exhibitionism, and similar taboo themes, without focusing on the humiliation, sadism, and threats.
There would likely be a shift in the clientele, but that wouldn't be a bad thing either considering how bad some of them are.
It will be interesting to see how it unfolds.