You definitely have a good understanding of the game, and most of your movesets are good.  One thing that might help this team would be to run a better starter. I suggest starting with Aerodactyl instead of Sceptile, so you can counter most of the common starters.

Sceptile ( M ) @ Leftovers
Overgrow
+ Sp.Atk - Atk (Modest)
% EVs:
~ Dragon Claw
~ Crunch
~ Leaf Blade
~ Detect

I suggest using Substitute instead of Detect, since it gives you a more definite form of protection. On Scepty, I use a Timid Nature, since it is faster than most things in the game. A regular 252/252/4 EV Spread (4 HP / 252 Spd / 252 SAtk) works well with him. Another set you might want to look into is the "Sceptic Tank" set. Leech Seed/Leaf Blade/Substitute/Focus Punch, Max HP, some SAtk, Some HP, and some Defense.

Flareon ( M ) @ Brightpowder
Flashfire
+ Atk - Sp.Def (Naughty)
% EVs:
~ Overheat
~ Iron Tail
~ Return
~ Shadow Ball

About the only thing you can do with Flareon is use Choice Band to exploit his huge Attack. EVs of 252 Atk / 252 Spd / 4 Def(or HP or SAtk). Moveset is good.

Wailord ( F ) @ Chesto Berry
Water Veil
+ Sp.Atk - Atk (Modest)
% EVs:
~ Surf
~ Ice Beam
~ Amnesia
~ Rest

Moveset is good. Bold with Max Defense, 64 HP Evs for a good multiple, and the rest in either SAtk or SDef. Probably SDef.

Dragonite ( M ) @ Leftovers
Inner Focus
+ Atk - Sp.Atk (Adamant)
% EVs:
~ Aerial Ace
~ Earthquake
~ Dragon Dance
~ Thunderbolt

The Smogon EV Set of 52 HP / 204 Atk / 184 Spd / 68 SAtk should work for him.

Aerodactyl ( F ) @ Choice Band
Rock Head
+ Atk - Sp.Atk (Adamant)
% EVs:
~ Aerial Ace
~ Earthquake
~ Rock Slide
~ Double Edge

252 Atk / 4 HP / 252 Spd. Hidden Power Flying works better on both him and Dragonite, but if you're using this for ingame, then I know the trouble that getting HP:70 causes.

Snorlax ( M ) @ Chesto Berry
Immunity
+ Atk - Sp.Atk (Adamant)
% EVs:
~ Return
~ Shadow Ball
~ Rest
~ Curse
Enough EVs for 300 SDef, enough for 200 or so Def, and 290 Atk. Put the Rest in HP.

Good Team overall.