Okay, Rotom-W... I wouldn't keep it because you have Raichu as an Electric-type, so I replaced it with a lead pokemon: Shuckle. This pokemon is one of the most annoying and hard to faint pokemon, so use it. Teach it Toxic, Stealth Rock (gen 4 TM), Mud Slap for accuracy lowering hax, and Wrap, mostly just to keep the foe in and let Toxic work wonders. EV train it in 252 Defense (Roggenrola's in Wellspring Cave), 252 Sp. Defense (Frillish on Rt. 17) and 4 HP (Ducklett on Driftveil Drawbridge). Give it a Bold nature.
Scizor: Is good, keep the moveset, and EV train it in 252 Atk (Route 1 Lillipups and Patrats), 128 Defense (Roggenrola's in Wellspring Cave), and 128 Sp. Defense (Frillish on Rt. 17). I gave it the Sp. Defense Evs so that it might be able to survive a Fire-type move. Give it and Adamant nature.
Altaria: If a Water-type comes along, you're pretty much screwed over, so replace Ice Beam with Dragon Pulse. Other then that, you're good! Ev train it in 252 Def (Roggenrola's in Wellspring Cave), 252 Sp. Def (Frillish on Rt. 17), and 4 HP (Ducklett on Driftveil Drawbridge). Give it either a Modest Nature or a Bold Nature.
Raichu: Keep Thunderbolt or Volt Switch, it's your choice. Forget Focus Blast (too inaccurate), Hyper Beam, and either Thunderbolt or Volt Switch. Have it learn Nasty Plot, Grass Knot, and Thunder Wave. Give it the Magnet and Ev train it in Sp. Atk 252 (Celestial Tower), 252 Speed (Basculin on Rt.1 while surfing), and 4 HP (Ducklett on Driftveil Drawbridge). Give it a Rash nature.
Machamp: You already have a Physical Tank, and I thought that it might be good to have a Physical Sweeper, so I chose Lucario. Teach it Earthquake, Extremespeed, Bullet Punch (breeding), and anything you want. Good options include Swords Dance and Hone Claws. Ev train it in 252 Attack (Rt. 1 Lillipup's and Patrats), 252 Speed (Basculin on Rt. 1 while surfing) and 4 HP (Ducklett on Driftveil Drawbridge). Give it the Life Orb to hold and give it a Naughty Nature.
Absol: Come on, make use of Super Luck! Give it the Scope Lens to hold, and teach it either Night Slash or Sucker Punch, whichever you want. Also teach it Psycho Cut for coverage, Stone Edge for coverage, and use Shadow Claw over Slash. Ev train it in 252 Attack (Rt. 1 Lillipups and Patrats), 252 Speed (Basculin on Rt. 1 while surfing), and 4 Hp (Ducklett on Driftveil Drawbridge). Give it a Jolly nature.
I wish you many wins and I hope this helps!