rules yes..but game mechanics? can any other army run and shoot? or embark in combat?
but yes you are right which rule to break
Harlequins can only get the embark during with a formation, and only Craft World Eldar have the Battle Focus rule (a rule they quite frankly needed because as an army they weren't that impressive for a while, and it's a rule that's well balanced. Also Eldar used to be the only army that could run (original fleet), so breaking the shooting phase to be an army of fast, fragile models is their "thing").