Can you use Crawns ability after you are no longer the active player and have played everything you want to marshall, your opponents has marshalled but you want to sneak in that 0 cost refugee that got discarded last turn?
Marshalling: Kneel Crawn Son of Calor to choose 1 Clansman card in your discard pile. You may play that card as your next action as if it were in your hand .
The as if it were in your hand suggests that you cant right?
If it were in your hand, could you do this? No.
Crawn does not permit you to do anything other than consider that card in your hand, which makes it subject to any restrictions marshalling a character imposes on your play.
Specifically, in order to play that 0-cost Refugee "from your hand," you have to pay it's gold cost. Even though it's gold cost is 0, it's still a gold cost. In order to take the action of paying a character's gold cost to play it "from your hand," it has to be your turn in Marshalling. In your scenario, it is not your turn in Marshalling.
End result: Crawn says you can "play" the card. You can only "play" characters when it is your turn in Marshalling.