yes
No, you cannot trade at that point. You can only trade Johto and Kanto Pokemon at that point. No Sinnoh/Hoenn Pokemon are allowed.
No, you don't need the National Dex to evolve Haunter in Pokemon SoulSilver. You just need to trade it with a friend then trade it back. Then, you have a Gengar!
That trade is not possible. Soulsilver cannot recognize Pokemon from newer versions.
no you can trade soulsilver pokemon to black
yeah you can
catch/ evolve/ trade / stones. The answer is too large to answer in once.
The only way to get a gligar in pokemon soulsilver is to trade with pokemon heartgold.
no you can't but you can migrate in into diamond and then trade it.
You'll need to trade for it from Pokemon HeartGold. It is not avilable in the wild in Pokemon SoulSilver.
of course you can
you trade
yes