ribbons 🎀
For the 1st one, I have done this! it will take some scripting, and customization. You can only attach one inventory widget and one equipment widget to a player at a time, so if you want more, you'll have to do some work arounds. I haven't messed around to see if you can make scroll bars to move up and down a list (but Im sure someone has done it), so I just used buttons to cycle through different widgets.
For the second one, you can just use global properties. 🙂
not sure about the last two, as so for I've only really messed with UI and Camera related things in RIAB, so I am inexperienced everywhere else. 😆