You need to learn Cold Weather Flying to fly in Northrend. If it's your first character on that account, you'll need to be level 77 to get it, either from Dalaran, River's Heart or K3.

It's not possible to solo wotlk raid bosses. Even if you were able to survive as prot against one, you'd most likely hit berserk timer before your wet noodle damage could kill him, which would still kill you.

You can do Burning Crusade raids, but def not wotlk.

If everyone has completed the battered hilt quest already, they are ineligible to loot any extra ones so they auto-pass on them. Before, you would auto-pass but wouldn't see the chat message. Nothing new here, just that it's now possible to see a group 'miss' a hilt if all players can't get it.