Seaside Urchin: Response: after you win an intrigue challenge in which Seaside Urchin participates, discard the top card of the losing opponent's deck. If that card is an attachment or an event card, Seaside Urchin claims 1 power.

Today, during a melee match the Greyjoy player attacked with 3 Seaside Urchin and after winning the challenge he activated the responses of each Urchin.

From the deck of the losing opponent were discarded an event card, a character and an attachment.

My question is: do all 3 Seaside Urchin claim 2 powers each, or only 2 of them claim 1 power (the 2 whose response causes the event and the attachment cards to be discarded)?

This should be clearer with the FAQ entry for self-referencing cards:

(3.12) Self-Referential Cards
When a card refers to its own name (e.g., the
Catelyn Stark (CORE S6) card that reads,
"Response: After Catelyn Stark is declared as
a defender..."), it is referring to itself only. This
response cannot be triggered when an opponent's
Catelyn Stark is declared as a defender.

So, the ability of each urchin is only referring to itself. Thus the two urchins which discarded an attachment/event both gain 1 power, the third gains nothing. This is also quite important for some cards such as the Core Set Jon Snow, whose reference to Jon Snow refers only to this version of Jon Snow, but the reference to Ghost also takes into account Ghost cards controlled by other players. (I feel almost ktomish now! )

Oly the 2 claim 1 power each.

Ok, thank you very much!