Q1: The lvl 15 Sorcerer attack Lightning daggers is causing some discussion at my table for 2 reasons.
The effect line of the power says: "Until the end of the encounter, you can repeat the attack as a free action once per round during your turn."

So does this allow the player to make the same attack as a free action during the same turn as the initial power was used? I would think RAI it wouldn't?

And does the free attack have to be vs the initial target or can you freely choose who to attack? The fluf line seems to imply the same target? but since it doesn't specify "against the same target" I would think it's not limited to one target?