Widget Area fields, Menu Fields, and Adding Widget Areas

I have two questions:

How do I pull in list of Widget Areas or list of Menus in Post/Page fields that I’m adding? (I’ve figured out how to pull in other types of fields that I create. But I want people to be able to select from a Drop-Down Menu a Widget Area while they’re creating a Post or Page.)

How do I allow users of the WP UI to make their own Widget Areas just within the UI, rather than going into the code? (I’m hoping something like this exists, but I don’t see any plugins that do the trick. And creating them within the code isn’t an option, b/c the people actually creating these websites and these Widget Areas can’t have access to the code.)