I like this. It looks so fun to use.
1. Move those 4 HP EVs on Sharpedo, Chandelure and Froslass to SpD. It might seem insignificant at first, but it does prevent Download Porygon2 from getting a Special Attack boost if it comes into them, and might reduce residual damage (uneven numbers in HP usually do).
2. Flamethrower over Fire Blast on Chandelure, its more reliable and you already have Overheat for power.
3. Hidden Power Fighting over Energy Ball on Chandelure - I'm sure Shadow Ball already 2HKOs everything Energy Ball hits, while Hidden Power Fighting lets you do some damage to Snorlax / Porygon2.
4. Lum Berry over Leftovers on Cobalion - getting paralyzed by Snorlax Body Slams and Porygon2 Thunder Waves / Discharges must really suck, and since Cobalion is already so resilient to residual damage, I would just go with Lum here.
I would definitely take a more serious look into Aura Sphere Raikou as well.
Great team man. Luvdisc'd.