If a card says that "engaged enemy does not attack this round" does that mean I still have to declare a defender?
No, but you may still declare attackers against it. It is still dealt a Shadow card, which does not resolve.
Also, in Escape from Dol Guldur... When the orc cheiftan (or whatever the character is) says I reshuffle an objective card... does that mean I put one of the 3 guarded objectives back in the deck? If so... OUCH.
Yes, you do, but only if you unsuccessfully quested.
Dungeon Jailer card text wrote:
Forced: If Dungeon Jailor is in the staging area after the players have just quested unsuccessfully, shuffle 1 unclaimed objective card from the staging area back into the encounter deck.