level 47 is when dewgong will learn ice beam
No,poliwrath cant learn icebeam unless you use a TM.
Dewgong learns Dive at level 45.
Dragonite can indeed learn ice beam, so yes.
Yes get the TM and use it on Swampert.
Heres a cheat: Go to celadon city and go into the game corner win at least 4,500 coins then go to the game corner exchange which is next door go to the far right person and take the first TM on the list the person will ask do you want the TM ice beam say yes and now go to the TM case and use it on your dewgong boom that was easy.
It learns it via TM.
Level 51.
depends on what level he is
You cannot obtain Ice beam as a TM in Crystal. You can only learn it from the Move Tutor in Blackthorn City. You can also catch: Seel, Dewgong, Shelder, Lapras, Articuno, Remoraid, and Octillary, and level them up to learn it.
Yes, Dewgong is awesome, because it can learn Ice and Water-Type moves, so you'd have no problem against Fire and Grass-Type Pokemon. Don't teach it Sheer Cold though. Signal Beam is a unique move for Dewgong.
Most water and ice types can as well as psychic types. Here are some examples: Mewtwo, Swampert, Vaporeon, Articuno.
The only way Staraptor can learn sky attack is through a move tutor in the Battle Frontier in Heart Gold or Soul Silver version.