Okay, aside from the issues addressed in the above post, there are some obvious issues with the way the team is currently built. It seems that you're approaching teambuilding with a singles mindset, with the most glaring signs in the use of Rapid Spin Smeargle and Brick Break CB Scizor. Bulky Toxic Dragon Tail Milotic, Thunderbolt + Shadowball Gardevoir, Roost Charizard are also all more singles oriented sets, though you do have some instances of Protect so it's obvious that you have a little doubles experience. I recommend that you try and avoid building for doubles in a singles mindset, understanding that the games are significantly shorter and the offensive output per turn is far higher, so you should try and tailor your team in that way. Another thing to note is that the tag you have is for Smogon Doubles, which is 6v6 lvl 100 battling, but online cart play is 4v4 lvl 50, so you should change your tag to note the correct tier. Anyway!!!! Here are some changes I recommend you consider that can make your team both a) more suited for doubles cart play, and b) more efficient.
1. Scizor: Choice Band Scizor is a very fringe set, and one I wouldn't say is necessarily bad, however it's definitely a more singles oriented set. That being said, I think we can make it work in a doubles context. The first change would be to switch out Brick Break for Superpower. The increased damage from Superpower lets Scizor get ohkos on things such as Heatran, Mega Kangaskhan, and most Tyranitar and Mega Tyranitar sets. Secondly switch Roost for Bug Bite, Tailwind or Knock Off. The speed of double battles means that you don't have time to switch Scizor in, Roost off damage, and then switch out. That's wasting 2 turns since it effectively makes it a 2 on 1 for the duration of that. However, if you do want to use Roost, I would consider switching to a Lum Berry set, since then you don't have to switch out Scizor immediately after healing.
2. Smeargle: Pretty standard Smeargle, though swap out Rapid Spin for either Helping Hand or Tailwind. Hazards have almost no use in doubles, and much less in 4v4 battles, since the games are much shorter. Helping Hand on the other hand offers the boost of a Choice item for your partner, and Tailwind can be used to avoid pesky speed tie scenarios.
3. Charizard: Pretty standard Charizard, however you should opt for Overheat or Focus Blast over Roost. Overheat in the sun guarantees you OHKO 4 HP / 0 SpD Mega Kangaskhan, and can be used as a nuke if you need to OHKO something quickly, as Heatwave + Overheat pretty much guarantees a ko on the whole meta. Focus Blast can be used to beat Tyranitars 1 on 1, and also helps avoid being walled by Heatran. Roost can be used, though it would best be done in conjunction with redirection, which your team lacks outside of Smeargle, who is really frail.
4. Gardevoir: You should run Destiny Bond and Will-o-Wisp over Dream Eater and Shadowball. Destiny Bond can help lure out and grab the KO on imposing threats such as Landorus-T, Mega Gengar and Kangaskhan. Will-o-Wisp can be used to cripple physical attackers that have a solid matchup against the rest of the team. I understand that the combination of Dark Void and Dream Eater may seem incredible, in application it is fairly underwhelming, and it either forces you to always bring Smeargle + Gardevoir, or to be wasting a moveslot on Gardevoir in some battles.
5. Milotic: Stall Milotic doesn't work in doubles (much like stall in general tbh), and Milotic should almost always be used as an offensive variant with Competitive instead of Marvel Scale. That actually benefits your team though, as now Milotic can be used to help keep out Intimidate users, and gives Garchomp some room to breathe, as it resists Ice type moves. I recommend trying a spread of 72 HP / 132 Def / 116 SpA / 188 Spe Modest Nature, with the moves: Scald / Hydro Pump, Ice Beam, Protect, Hidden Power [Rock] or Recover. The EV's let it always live an Adamant Mega Kangaskhans Return, a Mega Manectrics Thunderbolt and has more than a 50% chance to live Thunder, and always lives a Modest Charizard Y's Solar Beam. The SpA investment always OHKO'd 252 HP / 72 SpD Sassy Amoonguss with Ice Beam at +2.
That's all I have for now, good luck friend, and happy holidays n_n7
