[Yokuutsu]

Well, if one of you does not have the pokemon (like...if you traded me a munchlax and I traded you a wurmple) it would count as a special trade and that costs 20k stardust but goes down based on friend level and can only be done once a day (period).

You must be close to each other.

I believe Alolan and event pokemon count as their own separate pokemon when trading, even if you have caught the normal edition (pikachu vs christmas pikachu), but I could be wrong.