Stadium 2 Data
1. Unlocking Doduo and Dodrio Modes
2. Secret Pokémon
3. Trading Pokémon Restrictions
4. Move Rememberizer
5. Crystal and Stadium 2
Unlocking Doduo and Dodrio Modes
In Stadium 2, you must unlock four different modes- Doduo RBY, Dodrio RBY, Doduo GSC and Dodrio GSC. The RBY set are from R1 and the GSC from R2. You obtain them by finishing Gym Leader Castle and the main Stadium events. You get the Doduo from the first one you clear and Dodrio from the second.
Secret Pokémon
By defeating your rival, you can earn two special Pokémon, at Lv. 5 (ID 02000, OT STADIUM). The R1 Rival will grant you a Farfetch'd with Baton Pass, as well as Slash, Swords Dance and Agility. The R2 Rival gives you a Gligar with Earthquake, as well as Poison Sting, Wing Attack and Counter. Wing Attack and Counter are breed-only moves, so this is a very handy prize.
YOU ONLY GET ONE OF EACH. Clearing a Rival event multiple times will NOT allow you to create a team of Earthquaking Gligar. If the one you get has bad stats, you are stuck with it unless you wipe your cart and start again. (Do you REALLY want to beat Challenge Cup R2 again?) A buddy might get a better one; see if he or she will trade it.
THE MOVES CANNOT BE BRED OR RETAUGHT. You cannot erase Baton Pass from Farfetch'd, send it to RBY and teach it Substitute, and be able to retrieve Baton Pass by any means. Also, breeding a male Gligar with Earthquake and a female Gligar will not produce babies with Earthquake. A male and female prize Farfetch'd, each with Baton Pass, has been tested and will not produce babies with Baton Pass.
Trading Pokémon Restrictions
Possibly the most annoying thing to unlock in Stadium 2 is the ability to trade Pokémon freely from GSC. If you upload a Pokémon from your Gold game to the Stadium 2 boxes, you will be unable to move it to your Silver game unless your Pokédex says 150 Caught. You cannot move any Pokémon that does not match your game's ID and OT from Stadium 2 boxes either. Once you've attained this amount, a Pichu will appear on your PC. It'll dance around and look cute. The problem here is that filling out your Pokédex is *SO* 1998- nobody cares about it anymore, so nobody does it. Catching Pokémon in GSC is much harder than in RBY, as well. Until you get 150, all you can do is trade between versions with the trade machine, which is only slightly faster than using a game link cable. Note that this does not apply to RBY.
Move Rememberizer
That's just a stupid name I gave to the 'You can relearn a TM, but not really' machine.
Challenge the Elite Four with a team of Pokémon from your cart (NOT A REGISTERED TEAM). Once you beat Lance, you can use the machine. You can do it at any time in either mode.
The machine works like this. Any attack your Pokémon COULD have learned, can be retaught. The game says TMs, the game is full of crap. TMs and breed moves do not apply; this only works with level moves.
An example. You level an Eevee up to Lv. 99. At that point, the Move Rememberizer will allow you to reteach any of EEVEE's attacks. If the Eevee is located on a Yellow, Gold or Silver cart, it can relearn Focus Energy if it doesn't have it already. If it's on Crystal, it can relearn Baton Pass. It doesn't matter where the Pokémon came from, it matters what cart it's on when you challenge the Elite Four. This is how Moltres can learn Flamethrower (without Crystal) and Articuno Mind Reader.
Now, at Lv. 100, your Eevee evolves into Umbreon. You've missed all of Umbreon's attacks, like Screech, Mean Look, Moonlight, Confuse Ray, etc. Not to worry- the Move Rememberizer will now work for Umbreon, and NOT EEVEE. If Umbreon does not have Focus Energy or Baton Pass, too bad- these moves are lost to you forever. Note that you can only reteach one move at a time.
However, your Pokémon's Level must be high enough to RElearn a move. A Lv. 5 Scizor is wasting its time- it can't be retaught anything other than Quick Attack.
This is how you can get any move you want from Pokémon that change movesets as they evolve. A Smoochum can level up all the way, gaining all of its moves, and then use the Rememberizer to gain any Jynx-only attack it might have missed (such as Lovely Kiss) once it evolves. Want Disable on your Mewtwo? Go get it. Want Houou's Sacred Fire if you're playing Gold? This is how you can pick it up.
Crystal and Stadium 2
There are a couple of things you should know about how Crystal and Stadium 2 operate.
First, until your Stadium 2 cartridge comes into contact with Crystal, it will work as if Crystal didn't exist. Crystal-only items will not appear in the directory and Crystal moves will not show up on the Pokémon's pages. Whenever the little color carts are shown, it will only show a Gold and Silver cart.
To update your Stadium 2 cart for Crystal, put your game into the Transfer Pak and go to the GB Tower. Save your game. This will unlock everything Crystal-related- Cross Chop breeding to Magby, the Clear Bell, Suicune learning Aurora Beam, etc. The Crystal game cart will also appear next to the Gold and Silver ones.
Crystal interacts differently with the GB Tower. First, it takes a hell of a lot longer to upload the 'full' game- 60 or 70 seconds, I think. Second, you cannot use Doduo or Dodrio modes without having first cleared the Elite Four. (Possibly Mt. Silver as well.)
However, if you haven't finished Earl's Pokémon Academy, you won't be able to see the Crystal updates until you do. You have to clear it before you can read any data on GS, so it'd be a good idea to get it done if you haven't already. If your game has been updated for Crystal, you can read the GS and C books all at once without activating Crystal again.