Firstly, I'd like to say really nice format. Clean, succinct, and very easy to see what's going on =).
Without recovery of their own, Gyarados and Jirachi would very much appreciate Wish support from Blissey. You can just replace Softboiled with Wish on Blissey's set and you'll be good to go. Gyarados in particular needs the healing, as it is your only Fighting-type check and you have no spinner and no way to stop SR going up turn 1. Jirachi's resistances can be used throughout the game, and its health can be replenished by Blissey to give it the durability it needs for a late game sweep.
Being a long time user of SpecsJolt, I would have to recommend against it. I find it is far too reliant on prediction, and as long as your opponent has a Ground type around it is pretty much useless I find. I agree with what IceTime posted and would suggest you go with a LO Jolteon:
Jolteon @ Life Orb
Timid (+Spe, -Atk)
4 HP / 252 SpA / 252 Spe
- Charge Beam
- Thunderbolt
- HP Grass
- Shadow Ball
With Life Orb, Jolteon approaches the power of a Specs Jolt, but retains the ability to switch attacks. After a Charge Beam boost, however, this Jolteon set far outdamages Specs Jolt, and makes an excellent late game sweeper. Charge Beam alone is powerful enough to get the guaranteed OHKO on Gyarados, and so Jolteon can outspeed and KO a +1 speed Gyarados with it and gain something from the process. HP Grass as Salamence cannot switch into Jolteon by any means, and you'll really appreciate being able to hit Swampert and Tyranitar for that bit of extra damage. I would really recommend against using Signal Beam, as the OHKO on Celebi is completely not worth it. Jolteon is immune to Celebi's Thunder Wave and Grass Knot hits it for a whole 40 base power, meaning you should be using Celebi to Charge Beam up, not kill it off. HP Grass can deal with Tyranitar just as well (read: not too well) and Shadow Ball gets that important hit on Rotom.
Good luck with your team =)