What configures a coin being eligible for gifting? After reading some threads here in the forum I found Mercy saying that you can only gift donated coins, but some other people said that you can gift even coins you got from selling gold in the website after 72 hours. Does it proceed that after 72 hours I'll be able to gift my coins I get from Trading?
Yes, you have to wait 72 hours. It has been changed multiple times so you will find conflicting information but currently coins from trading and gifting can be used on trading or gifting again after 72 hours.