Is there any way to get data from an unloaded map?

There’s basically a way to achieve your overall objective already, very basics – you can tag playerstarts, and then have the player start at the tagged point when the level loads.

Anything more intense than that, such as recreating level state, or player progress state, or whatever, you’ll have to roll your own.

To actually do what you’re asking about, I don’t know if there’s any way to do that by default from the editor, but you could fairly easily write a Commandlet that would load each of your maps, query it for some information or other, and then write it out somewhere where you can use it later.

You could probably slightly abuse the built in automated testing plugin to do the same thing from the editor, if there’s not already some way to do it (or I guess you could probably do it in a Blutility…)

There’s probably a lot of different ways you could get there, but you’re going to have to design something that takes into account whatever you need to ultimately have it do.