Using Jolteon + Starmie + Dragonite as a team seems ok, though Salamence might be better with Intimidate. Jolteon + Scizor + Dragonite is also fine with the Dragon + Steel resistance combo. If you are using Jolteon-Starmie-Dragonite, Nite should just be physical, or at least it should be primarily physical (but apparently yours is mild, so I'm not sure if you are willing to breed for another one, or just go with Draco Meteor + 3 physical attacks, but without Extremespeed or Superpower it'll be hard to justify using an Inner Focus Nite over Salamence).
I've had success using this Jolteon: Modest @ Choice Specs: TBolt / Volt Switch / HP Ice / Shadow Ball. Modest was fine and just gets me a lot more attacking power, but Timid for outspeeding a few more threats is definitely good as well, so you can give that a consideration. If you are not using Jolteon, then there's less of a need to use Dragonite (for Ground move switching in).
Subway Starmie should ALWAYS be Timid @ Life Orb / Expert Belt / Choice Specs: Surf / Ice Beam / Psychic / TBolt ... You can use Grass Knot instead of TBolt because of Jolteon having TBolt if you want, but other than that, I don't see a reason to use what has been proven to work decently well.
For Scizor, yeah, basically what TM13IceBeam said. If you suck at prediction or just don't want to be choice locked though, you can also try SD > U-Turn and hold a Lum Berry or Sash or what have you. I'd use Lum myself since this is the thing to switch in for ice moves (assuming no Starmie) and freeze hax is annoying. Also, Scizor's lack of speed means it is prone to status as it SDs. There also seems to be more Swagger users in the subway than before, so you can use that to your benefit. If you ARE using Swords Dance instead of Choice Band, then there's less of a need for Superpower > Brick Break, but either are still fine.
I would advise having at least ONE (probably at most 2) stat boosting moves (like Dragon Dance / Swords Dance / Calm Mind) in your team for you to fight against defensive pokemon that will otherwise wall you, UNLESS you put toxic on something, but not mamoswine. If you are going the toxic route (for one pokemon), you need that pokemon to be fairly bulky to begin with. I've had success with a defense-oriented Gyarados and Eviolite Porygon2 as well as Calm Mind Suicune. Others who posted records also had success with Milotic. Keep in mind that there are a number of stat boosters in the subway that have rest also, so toxic might not be the answer to all defensive pokemon.
One last thing is, if you're not using Jolteon, Terrakion is fine, as its fighting, ground, grass, and water weaknesses are all covered fairly well by Dragonite. In that case Dragonite can be mixed. Stone Edge is going to end your streak earlier than you'd like when it misses, so I'd just recommend Rock slide instead, and even that misses plenty. Swords Dance over Retaliate is recommended. Focus Sash or Life orb are your best bets.
Only use Mamo if you are not using Jolteon but still want a Twave immunity. I would put a sash on this guy, unless you want to be able to guarantee OHKO on most of the dragons without being choice locked... then you use Ice Gem. Ice Shard and EQ are a must. You kind of want to be Adamant though.
Anyway, those were just my random initial blabbering thoughts that came to mind as I read. Hope it leads you somewhere and good luck.
If those pokemon were all I had I would probably use Choice Specs Jolteon, some sort of mix Dragonite (*might* even use a choice scarf one... speed is really important), and SD Scizor.