No, you cannot trade between the two different versions because the Pokemon are different or the Pokemon know different moves that are not in red version. When they re-make gold and silver for DS there may be some way to trade between Pokemon fire red and leafgreen to the new gold and silver but I doubt it.
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There is no NPC who you can trade a Haunter to for a Gengar in Pokemon Crystal. To get Gengar you will need to trade with another player or a copy of Pokemon Gold, Silver or Crystal.
Ask someone with a copy of Red/Blue/Yellow/Gold/Silver/Crystal to trade with you. Have them trade any Pokemon with you, and then trade the now-evolved Machamp back to you.
yes you can transfer a egg by link cable in the versions gold/silver/crystal. but u cant trade eggs to red/blue/yellow/green.
it's impossible to get remoraid. trade it from gold or silver.
If you can trade Pokemon from crystal version to gold version my guess is yes