your questions regarding the game rules (improving the interpretation).

By the way, is it possible to take the Goblin Outpost?! After all, it will provide a bonus for the desert.

Owner of the Snows - Yes, both are allowed, and they will repaint the outpost in turns. But if one stays overnight in the outpost, how can the other repaint it if he warned that the guard is not defeated and it is forbidden to attack? Is that absurd?! Or is it first come, first served.
2.6.3. It is allowed to enter a neighboring zone without defeating the guard of the passage in order to visit an object belonging to that zone, in which the player is located.