Card text is quoted below for reference.
My question -- if you use Small Target and it succeeds, is the enemy still considered to be "attacking you?" Would O Elbereth be a legal play after successfully using Small Target?
Small Target:
Response: After a Hobbit hero you control exhausts to defend an attack, choose another enemy engaged with you and reveal the attacking enemy's shadow card. If that shadow card has no shadow effect, resolve this enemy's attack against the chosen enemy. If that shadow card has a shadow effect, resolve this attack as normal.
O Elbereth:
Response: After an enemy attacks you, put that enemy on the bottom of the encounter deck. If your threat is lower than that enemy's engagement cost, set your threat equal to the engagement cost of that enemy.