Mamoswine looks like it could cause your team some problems. Celebi with so few Defensive EVs takes a large hit from Ice Shard. I would consider using many more HP EVs, since it looks like the Speed is largely unnecessary. The opponents you listed that Celebi beats are all outsped with no Speed or outspeed you anyway (Fidgit). I would consider going Bold or Modest and moving the Speed EVs into HP.
Gyarados is looking like a huge problem as well. I don't expect Revenankh and Kitsunoh can do that much damage to it before it pummels them, so you're forced to depend on Celebi's Leaf Storm.
Aside from that, it looks good to me.
Also: Unaware does not ignore Life Orb.
dan likes to ramble
<@Fatecrashers> im really gay
<@Fatecrashers> and i might fart rainbows