One problem with babying Gastly is that an Exp Share does not yet exist (and probably appears about the time you happen to evolve it), so it's switching it in and out every battle, not unlike RBY!Magikarp. Yeah actually, Scizor is too likely to end up with Wing Attack seeing how you'd have to either farm an early Metal Coat or keep it at L<30 before boarding the ship to Kanto. You can later teach Steel Wing when you reach Rock Tunnel (I don't know why this TM is given you twice during the game, and both so late), for Scizor's best STAB. I guess that typing is a big boon. You should try making a list of GSC Pokemon with better coverage than Lanturn; you'll run out of mons pretty quickly. Surf before the fourth gym is a big deal, given that you get it for free and it more than lasts the entire game, L25 Spark is nearly unprecedented, Icy Wind gives mini-boltbeam coverage.