No, no no... we're not going to get into all the bullshit complications of thinking about things like whether or not a poke should get this or that move because RBY has no breeding, tutors, later gen TMs, etc. In fact, worrying about those things completely ruins the point of this thread. If the Pokemon gets the move by any means in any game, it's legal here. Keep it simple.
Twineedle Scolipede is fine. Though it is still not going to help against those damn Psychics...
I'm glad people are enjoying this thread :D
I'd like to take the chance to start some discussion on the Pokes that go from fantastic to... not so fantastic too!
Tyranitar
Rock
HP: 100
ATK: 134
DEF: 110
SPC: 95
SPE: 61
-Rock Slide
-Earthquake
-Hyper Beam
-Surf / Blizzard
So, Tyranitar is really faces a mixed bag, of mostly problems that come with retrofit. Losing Dark type means losing some big weaknesses, but it also means losing TTar's primary role of Psychic spook (Psychics too powerful!!!), and losing Sand and its special defense boost is even worst. Rather than comparing it to what it is in other gens, it's almost easier to compare it to Rhydon and Golem, the Rock/Ground types that are omnipresent in RBY OU.
Lacking a Ground type is definitely a problem, because TTar can't wall Zapdos and is prone to some major damage from random Thunderbolts (and paralysis from T-Wave). No STAB on Earthquake sucks too. Interestingly enough, Tyranitar can easily beat Rhydon and Golem 1 on 1 though, thanks to superior Speed and access to Surf! Blizzard still hits them hard, but also lets you do SOMETHING to exeggcutor (did you ever think there'd be a day where Exeggcutor was a Tyranitar check...) 61 Speed is extremely trolly as always, being deceptively fast for such a slow Pokemon (with poor Speed being Tyranitar's only poor stat). Tyranitar also differentiates itself by being able to use Special attacks.
Overall, TTar is still really interesting, but no Ground type is a big minus when comparing to Golem and Rhydon.
Salamence
HP: 95
ATK: 135
DEF: 80
SPC: 80 (over 110)
SPE: 100
-Earthquake
-Fly / Double Edge / Rock Slide
-Hyper Beam
-Hydro Pump
movepool, movepool, movepool... Salamence is a sad puppy. If you thought mence had a fall from grace in BW... lol, we got some major issues here in RBY. Salamence has no Dragon STAB to use, not even on the Special side, and its only Flying attack is Fly. As a result, it has to rely on Normal attacks or Rock Slide to combine coverage with an un-STABed EQ. On the bright side, it does get Hydro Pump to kill Golem and Rhydon... um... that's all... No Dragon Dance... :(
On a sad note, Dragonite outclasses it because Dragonite has all those cool elemental attacks, and Agility plus Wrap.
Garchomp
HP: 108
ATK: 130
DEF: 95
SPC: 80
SPE: 102
-Earthquake
-Slash / Rock Slide
-Hyper Beam / Swords Dance
-Surf
Garchomp is a weird case because while you'd think the retrofit would weaken it significantly, as it loses Dragon STAB, it's lucky to get just the right moves in the right places... First, it has access to Slash, giving it a 140 base power attack to throw around with its STAB EQ. The sand shark also had Surf snuck into its movepool, utterly useless in other gens, but amazing to destroy Golem and Rhydon in RBY. Also for once it's glad it has Swords Dance instead of DD. Do keep in mind that Swords Dance boosts don't work with Slash, as critical hits in RBY ignore offensive stat boosts. When using Swords Dance, Rock Slide is probably a better bet to take advantage of the boosts and get some nice super effective damage on EVERY flying type, the only things avoiding EQ sincere there are no levitate Pokemon.
It's also... amazing... statwise, as always, with great bulk, great power, and stupidly trolly good Speed. It's even more awesome when you consider that Ground types in RBY are purposefully made to be really slow because of their immunity to omnipresent Thunder Wave that every RBY team uses to deal with everything... except a Garchomp. It seems that Garchomp was perfectly built to troll in any generation...