Rate my pokemon team?

Competitive Battling: 0/10. Why? Because Double Team is banned in competitive play.

Otherwise (basically if you dropped Double Team): 2/10.

Celebi: If any opponent uses Taunt, you're pretty much screwed over, forcing you to switch to an attacker, giving your opponent time to set-up on you instead. Same thing if they Whirlwind or Roar you into using Celebi.

Tyranitar: I would need EVs and Nature to determine if it is mixed enough to run Thunder since Tyranitar is more of a Physical attacker. Also its ability will create a headache for a couple members of your team if they are switched out into it.

Togekiss: Togekiss isn't a fighter. Sky Attack and Fly suck. If you want a Flying-type attack, Air Slash is much better. Togekiss is more of a supporting Pokemon so Extremespeed isn't the best choice on this Pokemon either. Try supportive or stalling moves on this thing.

Metagross: Since you're using mixed attacks, again, need Nature and EVs to determine if that is the best choice.

Swampert: Leftovers won't do you any good. A single Grass Knot and most hard-hitting Grass-type attacks will make it go KO pretty fast with Leftovers not doing you any favors. It won't do you any favors anyway even with those threats. Swampert is much more physical rending Muddy Water and Surf very useless. Try Waterfall instead of Surf. Try tutoring Ice Punch as well.

Abomasnow - GrassWhistle is very inaccurate. Due to its poorer speed and defenses, it's more of a supporting role so you don't strong attacks on it like Wood Hammer, which just would end up killing it faster. Furthermore, Hail hurts all of your team but it.

You have decent Pokemon, but there isn't a whole lot of synergy with it considering one Pokemon will end up hurting the rest of your team for a while (Hail) and the other hurts some of them (Sandstorm).

Overall a pretty good team, but as you have stated you don't have any fire moves. But, even with one fire move it won't make much difference.

You should probably make Tyranitar forget Crunch and teach it Flamethrower if you really wanted to. Togekiss' attacks are pretty powerful.

You may also want to teach Celebi some more offensive moves, like even Magical Leaf. (Just find the Move Tutor if you want to retrieve old moves ;] )

50/50 better moves maybe

its good