First things first. Never use 2 attack moves of the same type on a pokemon. It's a waste of space.
Now on to the suggestions
Blaziken
@ Charcoal
Slash
Double Kick
Fire balst
Sky Uppercut
try
Blaziken @ shell bell
flamethrower (better accuracy, more pp than fire blast)
brick break (better accuracy, goes thru reflect/light screen)
rock slide (egg move bred from camerupt)
bulk up
Grumpig
@Kings Rock
Psychic
Secret Power
Confuse Ray
Bounce
Grumpig's attack stat isnt any good so drop the secret power and bounce.
Maybe try
Grumpig @ chesto
Psychic
Confuse Ray
Magic Coat/Reflect
Rest
Sharpedo
@ Mystic Water
Slash
Surf
Ice Beam
Crush
Replace slash with return (105 power over 70 power) and im assuming crush is actually crunch?
Roselia
@ Miracle seed
Gigadrain (PP of 7)
Magic Leaf
Stunspore
Leach seed
Again you have 2 moves of the same type... Roselia has nearly no survivability and is only useful for aromatherapy. If you want an attacker grass pokemon try something like cradily or bellossom. But if you want roselia here's a moveset.
Roselia @ leftovers
Trait: natural cure (the poison trait sux)
giga drain
spikes/leech seed (for spikes breed w/ cacturne)
aroma therapy
Rest
Plusle
@Quick Claw
Thunderwave
Thunder
Quick attack
Fake tears
Plusle is really not a very good pokemon. It has very low survivability and crappy stats (like most of the available electrics in R/S) I would suggest going with manectric or magneton (manetric looks better for your team). If you really want plusle try this one.
Plusle @ leftovers or something like focus band
Thunderwave
Thunderbolt (more accuracy, more PP than thunder)
Fake Tears
Hidden Power (water)
But that one would be a pain in the butt to get with the right hidden power and without it, it is useless (all they have to do is switch to a ground). So maybe consider this instead
Manectric @ leftovers/shell bell
t-wave
thunderbolt
roar
crunch or bite for the flinch
Aggron
@ Soft Sand
Iron tail
Strength
Earthquake
Rock tomb
Not too fond of aggron personally (4x fighting and ground weakness hurts). But here is a moveset that could potentially work.
Aggron @ chesto/lum
trait: rock head (so you dont kill yourself with double-edge)
earthquake
double edge
iron tail, roar or iron defense (to try and cancel the 4x weaknesses)
rest