Friend, I look at your 'question' and I conclude that you are more knowledgeable and passionate about pokemon that I am. It's also pretty awesome to find someone still playing Pokemon Fire Red at this time of the decade. Kudos!
In any case, good job with your Jolteon, although I'm quite doubtful of the Baton Pass. This specific move is especially useful, and may in fact only be used in professional battles, when the pokemon who USED the baton pass has his stats up, because these stats carry on to the next pokemon. For example, a Linoone uses Belly Drum, and then uses a Baton Pass to a Gyarados, that Gyarados instantly has his Attack leveled up by 6 levels. Without any stat increase, Baton Pass functions just the same as switching out your pokemon for a new one manually; Baton Pass, if I remember correctly, doesn't give an extra turn to the pokemon that substituted the last one. It will still take the damage directed to, in your case, Jolteon.
I normally would suggest Last Resort, but that's for the 4th generation. So... if your Jolteon is Female, then Attract would be such a good move. Items are not allowed in multiplayer battles, so there's a high chance that the attract would stay there for a loooong time. If it's male, or if you simply prefer it, Thunder Wave. :D
But, it's just preference, though. Just an opinion from a guy who has long since distanced himself from the world of Pokemon, but is huge fan nevertheless.
Good luck! :D
P.S. I find nothing wrong with Thunderbolt-Shadowball as your only two attacks. Jolteon doesn't last long enough to face 3-4 enemies anyway, and there's not much pokemon who are resistant to both Lightning AND Ghost type moves.