Hi fire r a g e, I can see you've put a lot of effort into this RMT and you have some pretty cool sets/team members. However, I think there are some changes to be made, as there are some big weaknesses to prominent threats.
First off, I don't particularly like choice locked Gengar. Why? Every single one of his moves has a corresponding immunity that would leave Gengar helpless and force him to switch out. Current set: Shadow Ball, Focus Blast, and Thunderbolt. Together, they have pretty good coverage (especially over Rapid Spinners) BUT Shadow Ball has a Normal-type immunity, Focus Blast has a Ghost-type immunity, and Thunderbolt has a Ground-type immunity, and can't hit Volt Absorb users. This leaves Gengar set up bait for threats like Thundurus-T, Landorus, Garchomp, etc. Furthermore, if they double switch and catch you on something other than Focus Blast or Destiny Bond, Tyranitar will instantly KO Gengar 252+ Atk Choice Band Tyranitar Pursuit vs. 0 HP / 0 Def Gengar: 336-396 (128.73 - 151.72%) -- guaranteed OHKO and that's goodbye. Scarf Gengar just seems a little too one-dimensional to me, and honestly begs for a Pursuit trapper or a priority user to come in. For instance, 252+ Atk Choice Band Technician Scizor Bullet Punch vs. 0 HP / 0 Def Gengar: 244-288 (93.48 - 110.34%) -- 62.5% chance to OHKO and 252+ Atk Choice Band Technician Scizor Pursuit vs. 0 HP / 0 Def Gengar: 326-384 (124.9 - 147.12%) -- guaranteed OHKO. Again, that's it. I know you want to keep your star, so I'll try and give you a way around these threats. Against Pursuit trappers, I think the best thing to do, is to set up a Substitute beforehand, and flee, having Pursuit break the sub and leaving relatively unscathed. If they DON'T have Pursuit trappers like the aforementioned threats, you now have the chance to fire off powerful moves while behind a sub. Even better, right? I know you like the appeal of Destiny Bond, so I ran that in the fourth moveslot, but Thunderbolt or HP Fire could be run there instead. Therefore, I'll suggest that you run this set:
Furthermore, on Hydreigon, I suggest running Earthquake > Substitute. Why? Because the two of his main moves drastically lower his stats. Draco Meteor will lower SpA by two stages while Superpower lowers Atk and Def by one stage each. Therefore, what's the point of running a Substitute when you won't be able to hit the next pokemon very hard at all? With moves lowering Hydreigon's stats, he loses much staying power, and so Substitute seems counter-intuitive.
On Ferrothorn, since I will run Stealth Rock on Landorus-T, put Toxic > Stealth rock to stall for even more residual damage and take down set-up sweepers. This works well with Protect on Jirachi as Jirachi becomes even more haxy; Iron Head/Protect on slower, bulkier pokemon that don't care about weak Iron Heads or Paralysis will cause them to be slowly consumed by Toxic damage and possible Leech Seed damage.
As mentioned by pokemon0078, you really do have a big Terrakion weakness. Terrakion will come in and squish the majority of your team. Especially frightening is the SubSalac set, as after a SD boost and the Salac berry activating, it has an extremely high chance to OHKO your entire team with just its STABs. The only pokemon with even a slightest chance of surviving the onslaught is Jirachi, who has a 75% of being OHKO'd by Close Combat after a boost (guaranteed OHKO after Stealth Rock). Therefore, Landorus-T should be run over Infernape, as it provides good defensive synergy (absorbing Electric moves for Starmie, tanking Fighting moves for Hydreigon, etc) and its weaknesses to Water and Ice are covered by Ferrothorn and Starmie, respectively. The Offensive Pivot set that pokemon0078 suggested would work wonders on your team, as it can deal with Terrakion fairly well through Intimidate, resistance to Close Combat and neutrality to Stone Edge, and good natural bulk. Also, this gives you a reliable Stealth Rock user and Earthquake off a base 145 Atk stat allows you to hit Terrakion. This is the same set as proposed before, but I'll write it again for convenience.
Lastly, dump Sunny Day on Jirachi, as that's really a bad idea. Jirachi is already weak to Fire, and summoning Sun to boost Fire-type moves is suicidal. Therefore, run Protect > Sunny Day to stall for possible residual damage and for passive recovery from Leftovers. Also, since you have Thunder Wave, the need for a fast scarfer is slightly less, and I'm not really sure where I would put one anyway. (Somebody else might propose one.) To change the weather, Hail on a slightly bulkier Starmie might work, but I"m not 100% familiar with bulky Starmie so consider pokemon0078's Starmie.
With these changes, you now have Gengar/Hydreigon/Ferrothorn,Starmie,Landorus-T/Jirachi. Good luck! Hope this helped!
tl;dr