Emonga is one of my favourite Pokemon in NU; it's fun and a blast. Imo, it would be better if you did the Air Gem + Acrobatics combo, and gave Emonga this set: Volt Switch/ Acrobatics/ Roost/ Discharge (or Light Screen). If you don't want to do that (since you're putting the EVs in Sp. Atk), then go: Volt Switch/ Roost/ Electro Ball/ Toxic. Used correctly, along with some well timed Roost, Emonga can be a good Toxic staller in NU. It's also an option to use U-Turn instead of Volt Switch, because the latter will have no effect against ground types. You can consider using Rotom-Frost, since you already have Emonga w/ Flying type. Besides, all Rotom forms have Levitate, so ground is still x0. Shell Bell... there's really no need. It's not that effective, so might as well use a Life Orb/ Pain Split set, or a Choice/ Trick set.
Zap Cannon requires set up, and once you switch out your accuracy will reset, so I don't feel that it's worthwhile; replace with Thunderbolt instead. Luxray: Ice Fang/ Facade/ Crunch/ Volt Switch or Wild Charge. Quick Attack is a horrible move, even with Guts. Facade's 140 base is much better. You can consider Foul Play on Electrode, since it deals damage calculated by the opponent's stats. I would go for HP Ice on Ampharos, since that covers Ground.