Electabuzz has always been my favorite electric type.
For Y you want to go with either a speed boosting nature, since it's spA is already amazing, or a spA boosting one for more power. Either way he excels at being the clean up crew, sweeping whatever happens to be left over at the end of a fight.
1. You can use an ability capsule to change non hidden abilities.
2. He's good for breeding. Mega Charizard X needs Adamant to deal as much damage as possible since he's probably going down quickly. Dunno about Y since I never used him or bothered to look him up.
For Y you want to go with either a speed boosting nature, since it's spA is already amazing, or a spA boosting one for more power. Either way he excels at being the clean up crew, sweeping whatever happens to be left over at the end of a fight.