Thanks for the reports! Second one first: there will eventually be a distinct ending/boss fight situation for slut mode, and slut mode is the only situation where you can switch outfits. This may be tweaked eventually, as you'll need to switch to certain ones in other circumstances, but in general this "bug" is just an artifact of re-directing slut mode to the normal ending for now. Once that content is added that issue will fix itself, but apologies for it being a little sloppy at the moment.
On the second one, I'm a little confused; would you mind clarifying some specifics so I can try to replicate? Is this happening in the normal mode with the fights, or slut mode with the stealth gameplay? In normal mode if you get stripped in a fight but win, you are briefly nude in sprite form before Mezz puts the jacket back on, but you shouldn't be able to change clothes, because it's still normal mode. He should give the same rejection as always. If he doesn't, and allows you to swap outfits, THAT'S the bug.