Unfortunately, no. You can trade Pokemon from older games to more recent games, but not send newer Pokemon back to older games. One reason is that the older games won't even have all the Pokemon that the newer games have, and they upgrade the gameplay as well, so it would be hard. If you trade all your Pokemon from older games up to newer ones though, then you can trade them with anyone.
yes you can just trade like you normally do
Nothing happens you just trade him and he leaves and you go on with your Pokemon journey
No, you most likely have to trade from Pokemon pearl, in my knowledge, at least
Yes
you can get it by getting a pichichu in pearl trade it to heartgold
No, but you can trade Pokemon only in HeartGold to Black
you can trade pokemon from heartgold to black but you can only transfer the pokemon in heartgold not trade it from black
yes. you can trade Pokemon from diamond, pearl, or platinum to heartgold or soulsilver.
trade pokemon
no, but use can use poketransfer from heartgold to white
you can trade Pokemon from heartgold and soulsilver to your diamond,pearl, or platinum.
You need to have a Pokemon hold the item then trade the Pokemon.
Trade it or have it as the starter pokemon.
AMAN
Trade!
Trade
You get him in trade.