For Stadium? Hmm.
Alakazam needs Thunder Wave over Psybeam. You only need to kill 3 pokémon, so I don't think Seismic Toss is necessary for PP. You can keep Reflect; that might be pretty helpful.
Sleep isn't as effective on Stadium, as they shorten the period of time your opponent can sleep. Plus, Sing isn't the most accurate of moves. I'd recommend Double-Edge on Clefable. Blizzard if you can, Reflect, and Rest. That should take care of a lot of things.
For Hitmonlee, Meditate, Hi Jump Kick, Substitute, and then Body Slam for Paralysis. Should be able to deal out some severe damage if you play right.
Omastar should take advantage of its high Special stat. Surf is a must, then put either Blizzard or Ice Beam on it. Seismic Toss for potential Water types (those are annoying, the only things Omastar has trouble damaging)... And Rest to be a tank. Sometimes doesn't work though because Omastar is so slow. But that's what Thunder Wave is for.
Cloyster is nice with Explosion, though you'd have to use it early or it's pointless, since they have the whoever-explodes-their-last pokémon-loses clause. Surf and Blizzard on it... Double-Edge maybe. Cloyster has no lasting power so you might as well deal as much damage as possible before it dies.
Overal I question your type variety... Two water types, both not very fast. I'd recommend finding team members with speed, as the only thing you have faster than a Tauros is Alakazam.