I haven’t had time to reply in detail, but in short - yes you can.
Is this a separate question, or are you both working on the same game?
There’s a logical problem with giving the player access to a map/navigation screen at any point they choose from a menu bar. During an interaction with an NPC if it’s not playing out how they like they could pick the map and just GTF somewhere else, so to make sure that doesn’t happen a lot of the time you are going to have to have the map disabled/inactive. While you could work around this by having a global map enabled flag, it’s honestly going to be easier to make the map a callable screen when the script reaches the appropriate points.
There’s another, deeper, problem too. Displayed screens (such as your typical stat screen) run off the underlying event dispatch system and are quasi-asynchronous. Called screens (of which menu and say are types) run off the scripted steps, and effectively “block” until the event dispatch sends them an appropriate interaction making them appear synchronous. It’s complicated, but running story script off events can get things tied in knots.