Originally Posted by Fat Twist of Fate
On Celebi, I'd suggest running the EV's you have with Grass Knot / Recover / Thunder Wave / HP Fire. I think this is the best set in the metagame as of now, and will basically help out this team as much as possible. Leech Seed is kind of overrated in this fast-paced offensive metagame where you end up switching a lot, and so does your opponent. Thunderwave will have to suffice for Salamence and friends, since HP Fire is more relatable to the current top-tier OU's. Note that with your current spread, HP Fire does not KO Scizor, but it does hit it for like 65-70%, so be weary when using it on Scizor, or you will be faced with a KOing U-turn in return.
I was editing all the time when you made your post, but look at the top for the changes. I gave Celebi Reflect over HP Fire, and some more SD with it.
I opted for Ice Fang on Gyarados, reasons stated above.
Still need advice on what to do with Heatran!
Keep 'em coming!