The other duplicates thread has got a bit convoluted …

Somewhere in there I got the impression that Ktom says that you can ambush a duplicate of a character in play

is this correct?

Assuming it is okj - what is the gold cost (jnfluence to be knelt) for the ambush of a duplicate character

On a simpler level, at what point is a card identified as a duplicate - technically I would have thought it onyl becomes a duplicate when attached to a copy of the same card already in play, however during the marshalling phase you have to identify the duplicate first in order to calculate the cost as being zero

Maybe the identification of being a duplicate and related cost is a perculiar marshalling thing? - i.e. lots of effects allow you to find/put a character into play and such characters are not recognised as a duplicate until they are actually in play

Putting a duplicate in "for free" is a specific marshaling rule in the Core Rule book. At any other point, the cost must be paid for the character as if you were putting the character into play. At the point it would reach play, it becomes a duplicate.

So, yes, you can ambush in a duplicate (if it has the Ambush trait, of coruse), but you must still pay the printed gold cost in Influence. So, if you have Rhaegal (QoD) in play and another Rhaegal in hand, you must still pay 4 Influence to put the duplicate into play using Ambush.