Snorlax: I'd prefer Body Slam, Hyper Beam, Earthquake, and Selfdestruct, since Snorlax's attack power is really nice and he has STAB from Normal attacks... If you wanted to keep Amnesia, though, I guess Ice Beam would fit well into that last slot. There's always a surplus of special attackers, though, so if I were you I'd go physical with Snorlax; that's his purpose. Also, don't use him to start off the battle. He's too slow and too valuable as a sweeper.
Starmie: Psychic is not needed; Thunderbolt is more important in that slot. That way, you have an Ice-Electric combo, against which nothing has a resistance. You might try Blizzard over Ice Beam, since Starmie doesn't have Ice type STAB, and the extra power comes in handy. You don't really have to worry about running out of PP; Thunderbolt gets a max of 24, and if you're in a PP war anyway you have a ton of Thunder Waves and Recovers to waste. In that situation you want more power to finish things off.
Jolteon: Pin Missile is nonsense. Thundershock is awful, no better than an Electric version of Scratch. Thunderbolt is a lot better. I'd go Body Slam or Sand Attack or something over Pin Missile... Jolteon has nothing to fight Ground types with, so you're better off switching out; and Thunderbolt can still do some decent damage to Grass types.
Chansey: Noooooooo!!!!!! You don't need more than one recovery move on Chansey, plus, think about it. With this set, you have three non-attacking moves, and one attack with a max of 8 PP. This Chansey won't do anything except frustrate the heck out of both battlers. Now, with Chansey, you do want more PP, because she lasts a lot longer than Starmie (reason being she has such a high special stat coupled with her insane HP). Softboiled is great; you want Thunderbolt and Ice Beam on her, as well as Thunder Wave to paralyze faster Psychics and stuff.
Sandslash: Hmm, not a fan of Sandslash; in my opinion it takes too long to set up and dies fast after that. Swords Dance powers up Attack, but since Slash always gets a Critical Hit in RBY, Slash completely ignores that Attack boost. Dump Slash for Rock Slide. That way, if you predict right, you could get in a nasty Super Effective shot if they switch out of your Earthquake to a Flying type.
Alakazam: That's fine, although I'd prefer Seismic Toss over Reflect. Reflect only makes a one shot difference when it comes to getting knocked out with physical moves, and not all of Alakazam's opponents will be physical. If you run into a Starmie you're going to be in serious trouble without Seismic Toss.
Overall, a nicely balanced team that's likely to work if you play it right. You do have a lot of special attackers, though, and if you can switch one out for more physical strength, it would be good. Otherwise Chanseys and such get very annoying.