So uhhh, no one noticed the Amaterasu was activated in the same eye as the one Itachi plucked out?!!!

Maybe there was no technique. Maybe Itachi had already transfered his eye in Chapter 388 and then the fight started. Also explains why he wasn't himself completely.

As for how he did the Amaterasu without the eye, whos to say he couldn't activate it in Sasuke's eyes like he did after he died?