All right, so Jolteon and Thunderbolt aren't an option. What about Fissure? If you can control the outcome of any attack, instant kill moves like Horn Drill and Fissure should be able to connect every time. You get Fissure automatically after beating Viridian Gym, and the stats of the Pokemon who knows it shouldn't matter.
EDIT: Okay, I lied. I very quickly discovered why Zapdos was picked up in the SDA run and in the speed walkthrough on GameFAQs - Lorelei's Pokemon are a HUGE annoyance if you try to face her with Blastoise alone. My strongest move against any of them is Dig - and it takes three Digs just to take out her first Dewgong, which has average defense. I don't even want to think about how many it takes to take out Cloyster, which has much much more defense.. I'll probably run through half my moves just to beat her, while the Zapdos is capable of one hitting her whole side. And then, I have to worry about the pair of Gyaradoses that Lance and Rival have (the ones I faced before take up to 3 hits to take out, when they're lower level than me.. these will be as many as 10-15 levels above me).. can't use too many Digs otherwise I wind up worrying about Agatha's Gengars.. yeah, I'm seriously doubting running through the Elite 4+1 is even possible with just Blastoise. So, I'm backing up to after I defeat the 8th Gym leader to pick up Zapdos as in the SDA run and continuing from there.
Just a suggestion-why not pick up Eevee and turn him into Jolteon? I would think it'd be faster, and I'd be very surprised if he couldn't use Thunderbolt to take out Lorelai almost as fast, even at a low level.
Phamtom Train : Will have to find a Fenix down somewhere
Actually, there's a couple of Fenix Downs in the Returners' Hideout. The closest one is probably the one in the treasure chest near the bed that Terra wakes up in.
