You must breed it with a Snover or Abomasnow that knows GrassWhistle (they learn it naturally by leveling up)
Any Pokemon can learn it. that's the best patr
Bayleef Does Not Learn Sleep Powder in HeartGold/SoulSilver
Headbutt is no a HM in Pokemon soulsilver. However a man in Ilex Forest will teach it to any Pokemon that can learn it.
Bite is an attack, and isn't a TM. The Pokemon has to learn it.
In the Platinum it is 44, but I am not sure about Heartgold and Soulsilver.
Only certain Pokemon can learn it but you can't find the TM
There are a lot of Pokemon that can learn Cut, a tip would be to look for a Pokemon with claws or something sharp on it. Here are some that can be found early on in the game, Treeko, Torchic, Nincada and probably Shroomish.
you should be lucky to be a treeko! he can learn a variety of moves at the start, such as pound, absorb, bullet seed, and much more, which will help against groudon quickly
there are a lot of Pokemon that can learn surf but mostly water type Pokemon can learn surf but did you know that snorelax and rydon can lean surf
Yes
Almost any rock type.
He should. Its water/flying