Is it possible to set/change any of the colours from a button.
Other than loading a theme or config backup, not in general. There are only commands for setting things like the accent color of a folder tab; things that you'd normally need to change on the fly.
Envision - I change my shared background from a dark to light one - having a button to change file/folder text colour from white to black would be quicker than going through prefs or changing theme colours - put it on the feature requests please.