I noticed that PO and Smogon ban certain move combinations when they're not actually illegal in-game. For example, Smogon's electabuzz analysis says that thunder wave and cross chop is an illegal combination. The PO team-builder also bans the thunder wave and heal bell combination on chansey. Why are these banned when they're possible in-game?
The only way to teach them Thunder Wave is by sending them back to Gen 1. Cross Chop and Heal Bell are both breeding moves and do not exist in Gen 1, so you cannot breed the moves onto the Pokémon then send them back to teach them Thunder Wave. Maybe there's a different method to teach them the moves, but that's all I could find.
You can use Pokemon Stadium 2 to trade the TM from gen1 to gen2. So basically anything that is a gen1 TM will be legal.
What? No you can't. RBY TMs get stored in the color case, GSC in the metal case. You can't go about transferring TMs (or any items, really) between generations like that. The only way to get RBY TMs on Pokemon in GSC is to trade that Pokemon to RBY itself, like Moogle said. To clarify, the criteria for an illegal moveset, assuming all moves are in that Pokemon's movepool, are as follows: 1) One move is either an egg move that only exists in GSC or an event move that only exists in GSC, and another move is a TM from RBY. 2) One move is an event move, and another move is either an Egg move or another event move. 3) Some set of egg moves are used that cannot all be on a single father. *Event moves count NYPC giveaways and special gift Pokemon from Stadium 1 & 2. Surf Pikachu does not count in this because it's not a gifted Pokemon, but rather tacking a move onto a Pokemon you already have.
That's pretty inconsistent seeing as GSC uses mechanical freeze and sleep clauses which are Stadium mechanics. Jorgen- Yeah you're right. I thought you could trade items between gens because I read that you could use PS2 to trade back water and skip to Saffron. Unless that's possible by having two carts inserted and trading directly, but I can't check that.