You can buy the Shadow Ball TM in Fire Red/Leaf Green in the Game Corner, if that helps.
On Scyther: He
is the strongest non-fully-evolved Pokémon, stat-wise, and Scizor has that ugly 4x fire weakness. Use whomever you like better. (I usually select my favourites out of the fully evolved Pokémon; I like Metagross 'cause he's pretty blue. :))
Continuing the rate:
[email protected]/Leftovers:
- Synchronize
Impish, 252Def/128HP/128SpDef
Curse/Mean Look
Shadow Ball/C-ray/Toxic
Baton Pass
Moonlight/Wish
The defense-raising berries aren't quite so useless when you're passing. The Cursebreon set demands Moonlight, but Wish can help if you're about to Pass.
[email protected] Berry:
- Synchronize
Calm, 252SpAtk/252HP/4SpDef
Psychic
HP:Ice/other HP

pecial
Morning Sun
Bite
Special stats with physical movepool. Why, GF, why? SynchroLum 'cause it's fun and destroys toxistallers.
[email protected] Bell:
- Static
Modest, 252SpAtk/252Spd/4Def
HP

pecial
Thunderbolt
Thunder Wave
Agility/Return/meh
or
[email protected]:
- Static
Calm, 252SpAtk/252HP/4Spd
Thunder
Rain Dance
Surf/HP:Water
Thunder Wave
Won't survive an EQ from anything, even with EVs+Bold, so just switch. Don't try the Thunderdance with a
[email protected] Ball, as it'll die upon Dancing.
Scizor/
[email protected]/Leftovers:
- Swarm
Careful, 252HP/128Atk/128SpDef
Silver Wind
Baton Pass
Swords Dance
Agility/Iron Defense
Could've saved a slot if he had Bulk Up or Dragon Dance, but he doesn't... :(
Take care. :)