Been a long time since I played Yellow, but I still have the game. Sorry to ruin your fun but if I recall correctly you don't fight the Squirtle squad or the abusive Charmander trainer you just get given their Pok?mon. You don't even really need to do anything just have the right gym badge I think. Also the Pikachu you get can't evolve which always annoyed me because Raichu is my favourite and I wanted one to follow me. Instead I had to wait for the Gold and Silver remakes. The surfing mini game was hella though.
That game sounds hella boring