x2Resonant Evolution
Once during your turn, when you play a Pokémon from your hand to evolve 1 of your other Eevee, you may search your deck for a card that evolves from this Pokémon and put it onto this Pokémon to evolve it. Then, shuffle your deck.
TackleIt has the ability to alter the composition of its body to suit its surrounding environment.
If my opponent has an Empoleon V with "Emperor's Eyes" Ability active, and I have both an Eevee with a Memory Capsule attached and an Eevee with the "Resonant Evolution" Ability in play, if I evolve the Eevee with a Memory Capsule into a Jolteon with "Thunderous Awakening" Ability can I use "Resonant Evolution" or not?
Yes, that will work because Emperor's Eyes has been disabled.
If I have multiple Eevee with "Resonant Evolution" in play, can each of them trigger if I evolve one other Eevee? Or do I have to evolve a separate Eevee for each one?
If you have multiple Eevee in play, playing a card from your hand to evolve 1 of them would trigger every Resonant Evolution.