You can NOT battle Professor Oak in Pokemon FireRed Version, even with an Action Replay
you cant
No
Catch, trade, and battle Pokemon
No.
You can't battle him. But you can find him in eterna city after you got the pokedex upgrade off him (he is in the empty house).
mr. Pokemon house
Pallet town in Kanto
ofcource you can
beet a gym battle
no
He won't. You only get one.
No. Growlithe is a Pokemon exclusive to Pokemon FireRed Version.