Reordering and Releveling Context Menus

There among the things that I would like to add to my Mozilla Addon is the ability to reoder the context menu, and move the context menu items for my addon one level higher to better mirror the old XUL addon which it replicates.

Is there a way to do either of these through the custom.css or with the menus.overrideContext API?

Note that I do NOT intend to do either of these as a part of my existing addon, but ONLY as a separate addon that would be specifically installed by the user.

For the first item, I am looking at the ability to do this:

Menu Before Menu After
Menu 1 Menu 5
Menu 2 Menu 2
Menu 3 Menu 3
Menu 4 Menu 4
Menu 5 Menu 1

For the “re-leveling”, I want to convert this:

To this: