I have a cause for speculation with the Passimian card from sm5.
Ability: Power Scrum
As long as this Pokemon is on your Bench, each of your Passimian’s attacks does 30 more damage to your opponent’s Active Evolved Pokemon.
The part that sticks out to me is that the ability clearly says Passimian's attacks do 30 more damage, it does not say "Passimian do 30 more damage" but instead the attacks of Passimian do 30 more, if mew from Fates Collide copies team play from SM1 Passimian, will mew get a 30 damage damage boost from what it was already doing to an active evolved pokemon because it is using Passimian's attack.
*Even if it doesn't work for Mew it makes me curious why that wording would be used.
Ability: Power Scrum
As long as this Pokemon is on your Bench, each of your Passimian’s attacks does 30 more damage to your opponent’s Active Evolved Pokemon.
The part that sticks out to me is that the ability clearly says Passimian's attacks do 30 more damage, it does not say "Passimian do 30 more damage" but instead the attacks of Passimian do 30 more, if mew from Fates Collide copies team play from SM1 Passimian, will mew get a 30 damage damage boost from what it was already doing to an active evolved pokemon because it is using Passimian's attack.
*Even if it doesn't work for Mew it makes me curious why that wording would be used.