My team for the E4:
Volcarona
Heat Wave - Bug Buzz - Quiver Dance - Will-o-Wisp
Porygon-Z
Triplette - Discharge - Dark Pulse - Thunder/Thunderbolt/Psychic/Thunder Wave
Mamoswine
Icicle Crash - Earthquake - Ice Shard - Blizzard (Only for Heather to change the field)
Heracross Mega
Pin Missile - Close Combat - Rock Blast - Bullet Seed
Metagross
Meteor Mash - Bullet Punch - Zen Headbutt - Earthquake
Togekiss
Air Slash - Dazzling Gleam - Thunder Wave - Nasty Plot
For Heather my biggest problem was Gyarados, Proygon-Z with a Focus Sash und Thunder took care of that. The next pokemon was Nidoking, Mamoswine with a Telluric Seed (+2 Attack in Mountain Field) took one hit from Nidoking to change the field to Snowy Mountain and sweeped afterwards with Ice Shard.
Against Laura/Bennett, Anna and Lin Volcarona with Quiver Dance sweeped. The A-Ninetales lead from Anna and Lin couldn't do anything against Volcarona. Setting up Quiver Dance to stall the Aurora Vail and easy win.
Biggest problem was Elias, but a Download boosted scarfed Porygon-Z with Triplette as well as Dazzling Gleam Togekiss took care of Elias.