Bad natures, and your movesets only are good against one type, really, I could make just two pokes and have them super effective against all 17 types if you combined them.

Sceptile@Rash(Rethink your nature and what you want, Sceptile is better at special sweeping FYI)
Shell Bell(Good choice in item, when coupled with Giga Drain)
Giga Drain(Keep this here, maximizes his ability to special sweep)
Dragon Claw(Dragon Breath, Or Dragon Pulse would be good here. That uses Sceptile's special attack more)
Leaf Blade(Focus Blast is a good option for this slot, but lacks accuracy. So it's risky)
X Scissor(Agility in this spot maybe. It's really up to you here, keep it to a stat increasing move or another special attack)

Arcanine
Bashful natured(Same thing, rethink your nature and what you're doing with the pokemon, you have physical and Special moves. Choose one or the other and maximize that stat. Arcanine's Attack is slightly higher than his special attack, so think about that when choosing moves.)
Focus Sash
Flamethrower(This needs to be changed with Flare Blitz)
Thunder Fang
Arial Ace
Extreme Speed
All moves look good except for Flamethrower.

Gyarados
Focus Band
Impish Natured(Same as before)
Water Fall
Earthquake
Ice Fang
Dragon Dance

This is the best moveset you've got! Just rework the nature to Jolly. Maybe Adamant, but Jolly would be best, because his speed is lower than his attack.

Bad natures, and your movesets only are good against one type, really, I could make just two pokes and have them super effective against all 17 types if you combined them.

You are at no place to comment on other people's movesets, especially negative things about others.