as long as you can charm the Foreman, you can do the quest. One note though, be very very close to him, and have a jade ON your cursor, cause he WILL break charm fast.
At 50 you might be able to solo the DE Mask camp, but if you get a lot of adds, you might end up getting killed. A healer on the side, or the pali, would enable you to do it easy. The mobs in the assasin room ar 35-40ish. You should get the mask to drop in an hour or two. If it was me, and I had a 55 druid, I would park the bard in the room, bring the druid and pali down there and kill like madmen till the mas dropped