Hi
Dunhere has that "Dunhere can target enemies in the staging area when he attacks alone. When doing so, he gets +1 ATK."
Goblin Sniper has that "During the encounter phase, players cannot optionally engage Goblin Sniper if there are other enemies in the staging area."
Can Dunhere attack the Goblin when other enemies are in the staging area ? It is not an engagement as I understand the rules, but just an attack so I think that he could, but since I'm a newbie at the game I cannot be certain