Thanks for the suggestions! Good news is that a good number of these are already in my backlog.
It'll take a lot of time to implement everything though, as I'm mostly working on this game on my free time... So some features like male characters have very little chances to ever make it to the game anytime soon (that'd translate into many, many more sprites = too much work tbh). But I'll definitely work on other less heavy features and have even already been thinking about the best way to handle a couple of them, like the afk mechanic or achievements. Achievements were actually part of my initial "specifications", and my first intention was to use the currently unused third tab of the inventory for it.