I don't use folding much myself, but this looks reasonable, perhaps fold users could comment.
But a couple of points, the keybindings should have menu equivalents so they are more discoverable or the actions usable if the keys are not bound. I don't like using up additional keys for default bindings, its already getting so there are not many left, so they would be unbound by default and the menu would allow occasional use of the functionality without binding them. Users with a high usage would of course bind keys to the actions.
I would suggest that in the `Document` menu `Fold All` and `Unfold All` with a single `Fold...` and a submenu with all the 9 commands.