Deoxys EX's "Power Connect" Ability refers to "your Team Plasma Pokémon's attacks (excluding Deoxys-EX)". Does that mean to exclude ALL of your Deoxys EX in play, or just one with the "Power Connect" Ability?
It refers to all of your Deoxys EX in play.
Source: Plasma Freeze FAQ (2013-05-16), TPCi Rules Team (2013-05-16)