Cheers, glad you like it
1. The keyholder can die or be released, I've left this in a a sort of risk thing. In this case the wearer of the belt is pretty much stuck. Be careful who keyholders are and how you treat them.
2. It's a bit of a mix, some of the events check if the character has a penis or not (while wearing a belt, a character does not have a penis as far as the game is concerned), while other events assume the character has a penis, even if they are female. Things are a little broken here so a little bit of roleplay/ignoring from the player is required at times. This could likely be addressed but would take quite some time. Allowing it if the keyholder was in the combat group and lenient is an interesting idea though.
3. I wasn't aware of away.duration == -1 being a thing. I've updated that now and will be in the next version.
4. I actually already redid the end of the "starting slave" sidequest for if the player is currently in chastity and the starting slave was chosen to be the "Keyholder" as the "starting relation". It is probably doable to have the player become caged if they are not already if certain choices are picked. I'm not 100% sure the best way to do this without basically replacing the current dom scene.