Dragonite needs some help IMO. If your using an offensive dragonite (which you are), then you should use an offensive nature. Try Timid or Modest. Dragon tail doesn't need the extra power boost. If you want a power boost then go for Dragon Claw or Outrage. However, I agree with Glory Blaze, right now you should replace it with Ferrothorn. Dragonite is accomplishing the same thing as zapdos is, except instead of speed it has Hurricane. If you want a good rain team dragonite then i recommend the following set.
Dragonite Mixed Attacker
Dragonite @ Life Orb
EVs: 252 Atk/ 252 Sp.Atk/ 4 Spe
If you really are adamant about using a dragonite, then this would be a far superior layout. Its able to do a few things for your rain team. The most important one is wallbreaking. Because most wall tend to focus on only one form of defense, Draonite can use Rain boosted Aqua Tail or STAB Hurricane to hit walls hard. Hurricane also doubles as a way to get rid of bulky grass types like Celebi, Virizion, the now popular Amoongus, and Venusaur, which you otherwise have a very hard time bypassing when they are played correctly. Roost should be used on almost all non-sweeping dragonites as it allows it to get the most out of Multiscale (the best thing to happen to Dragonite since RBY). Extremespeed isn't the most powerful move, but it will bypass Dragonite's horrid speed, making it very useful for picking off frail weakened sweepers and such, as once a sweeper sets up, I don't think your team could do much if the sweeper outspeeds or resists Zapdos's moves
Starmie's item is fine. It will trick people into believing that it is choiced, which will come in handy. However, if your using Starmie as a Rapid Spinner, then leftovers is always a wonderful option.
Also heads up, Lucario isn't checked by magnezone. It outspeeds and KOs with Close Combat/ Aura Sphere.
Also, Zapdos does not need to be using Hidden Power Fire on a rain team. Magnezone can get away with it since its sole purpose is countering Scizor and Ferrathorn, but it wont fly with Zapdos. Its damage in the rain is pathetic (even when 2x Super Effective). Change it to Hidden Power Grass. You already have dragonite to deal with the bulky grass types that now Wall Zapdos, but you can take out Gastrodon and other ground types now. While the dragon type itself resists Electrc/Grass, most Dragons have a dual Flying typing, so Thunder should be sufficient to brute force them.
Oh and you desperately need a sweeper. I would change Toxicroak to a Calm Mind Keldeo set