The leaf storm misses didn't cost you the game. Had you hit the first and killed my pikachu, then you would've had -2 attack. Heatran quad resists that leafstorm and a -2 attack leafstorm followed by a -4 attack leaf storm would fail to 2 hit ko me. Don't complain about my Snorlax living either. 1, judging from damage that first one did to me I would've lived another earth power and I did. 2. You got a special defense drop with the earth power, so I wouldn't be complaining about mix max damage. If you didnt get that drop I would've easily lived with more than enough hp to come back in on stealth rocks and make your celebi drop even more special attack. In all, the Leaf storm misses did not matter; it actually helped you get a full power attack on Heatran.
We wouldn't even be talking about the Snorlax survive if you didn't get that special defense drop.