Sorry for being late man, but I'm here to thank you for those suggestions. The team works really well after those changes and I reached 1500 ELO which I never would've thought, or at least in such a short amount of time! :)
Ferrothorn is so fricking bulky and WAY better than Skarmory, and even acts as a pivot and Fairy-check.
I don't really get to use Stealth Rock on Necrozma, since I usually use it to outspeed mons in its burst form which my remaining team can't. Is it worth having Stealth Rock on it, or should I give it to Ferrothorn?
Overall, the team is amazing. Here are some replays I saved:
1600+ opponent:
https://replay.pokemonshowdown.com/gen7anythinggoes-1396859470-591aadsxp1y0ns2t5wzx71994uwmiv4pw
I did beat another 1694 opponent, but didn't save the replay lol.
Outplaying this dude a lot:
https://replay.pokemonshowdown.com/gen7anythinggoes-1398215637-6a5s9hf0vs95d7r8ow254aa8x7te9jmpw
Making a dude rage quit in JUST 6 TURNS:
https://replay.pokemonshowdown.com/gen7anythinggoes-1398269199
Thanks. :)