Well I personally don't really like Ninetails, so save your self troubles. I think that you should get a Houndoom to use as your fire type pokemon. The reason why I say that is Houndoom is a very solid Fire and Dark pokemon, and is one my my favorite Fire Pokemon. If not Houndoom try to get a Magby, and eventually evolve it into a Magmortar. Both Houndoom and Magmortar are solid fire type pokemon, and Magmortar can even learn moves such as ice punch and thunder bolt from TMs.
Now for your Physic. Jynx isnt a bad choice, but I feel that Alakazam is better. In addition, I think you should maybe try out Bronzor, which will eventually become a Bronzong. Bronzong is the pokemon I used as my physic for my Pokemon Platinum Playthrough. Being a Steel and Physic Type, gives you an advantage against pretty much all pokemon besides either Fire or Ground. Bronzong's ability is either Heatproof (stopping fire moves) or Levitate (stopping ground moves) making you only have to worry about either Fire or Ground, while using Bronzong. If you decide not to use Bronzong, definitely go after Alakazam.
Now for you Leafeon. Leafeon only learns Leaf Blade out of all of those moves, which it learns Leaf Blade at lvl 71, pretty much not allowing you to use that move throughout the entire game. Personally I don't feel like Leafeon is that good, but Besides Roserade and Torrtera, Grass type pokemon fall short.
If you must use a Grass Type pokemon, I prefer Roserade, but otherwise, I think a solid, Ground, Rock/Bug, or Electric type pokemon would replace the grass type, based on your teams.
And if the worst comes to the worst, try out a good Flying type, such as Driftloom,(Ghost/Flying), Togekiss, or Staraptor.
And about the trading, I'm not really sure. But to tell the truth I don't think so. If anything find a friend to help you out. I would help, but I traded in my Platinum.
And last but not least, Dragonite is a great dragon, but I personally prefer Garchomp. Garchomp is a Dragon/Ground Pokemon and could be found early in the game. Since it is Ground/Dragon, it almost has no weaknesses, except against its own type.
I hope I helped