Two-on-two would be better terminology. In 2-on-2 battles, both players use 2 Active Pokémon and up to 4 benched Pokémon. This form falls under the unlimited-fun format.
And I was referring to the entire game rules, under which Weavile's power falls. Furthermore, since you did not specify that it was for Weavile's power, how was I supposed to know you were talking about that?
Anyway, as far as Weavile is concerned, his wording (each of your active pokemon) is made that way so it works for 2 on 2 format. A lot of cards have that (Pick one of your opponents active pokemon......each of your active pokemon....one of your active pokemon...), but in general play, you should just read this wording as "Your active Pokemon", which is only one.