There are 69 trainers you can battle in Pokemon Sapphire. This also includes the Gym Leaders and the Elite Four.
There is always four trainers and one leader.
No, you can't steal Pokémon from other trainers in Pokémon Sapphire.
No
Trainers school in Rustburo
train all your Pokemon equally
Yes
trainers don't hold them get a Pokemon that has the ability pick up like meowth or zigagooon
use psychic Pokemon and beat all the trainers to get more light
use psychic Pokemon and beat all the trainers to get more light
Nothing. You don't battle any other trainers or nothing.
There is no vs. seeker on sapphire pokemon. there is something on the pokenav called trainers eyes. trainers eyes = vs. seeker
There are many Pokemon you catch that are similar in sapphire and emerald but there are many Pokemon emerald can only get and not sapphire.