Oh wow, great feedback! :)
So funnily enough half of what you said I had slated for this game but ended up shelving for a second more complex pet game later once I got further along and realized how much work it was lol. This game definetly ended up being very much a tamagachi original omage.
Some thing's I left for the user to figure out like the original, but it also seems that its just as confusing now as than. I can do some extra things to show what the monster currently wants.
Honestly I like pretty much everything you said, I just gotta think on how and if I can make it possible.
Not pets for the pet, or marriage though. My codebase just can't support that and I need some extra cash to buy the new tamagachis to study lol!
Stay posted, I will be making a post on reddit and here in the next weekish or less going over everything I plan to add, or already added for the next update.