Tunnel does not require combat if you have Fire(which you should have if you've unlocked the south forest). Simply wait at the edge of the bottom right bandits' 4-tile aggro radius and rush from the vine to the bed once they look down. Apparently you don't need the tunnel, but I'm telling you anyway.
Lack of Charlotte when Aura has NG+ stats mostly means a delay on the Minotaur and Low-Demon since you should be able to kill the Slime and Young Spider Queen without her. Being a lower level doesn't affect the strength of her Heat Up either, just that of her Fire.
As a tip, the room unlocks do not count as mental changes. Free -3 corruption in the outer chamber without if affecting your score.