A faction "(un)playable for player"

[Konrad Klar]

Playable on a unique non-Dragon faction. Place a Border-hold from your location deck off to the side with this card. The Border-hold must be in the same region or adjacent there to a site where the target faction is playable. Return any faction playable at the Border-hold to its owner's hand. -5 to any attempt to play a faction at any version of the Border-hold. All versions of the Border-hold gain an additional automatic-attack: same type as your target faction-5 strikes with 9 prowess (detainment against your companies). Cannot be duplicated on your faction.

Scenario:
Doors of Night is in play. There is a M/H phase of company at Lossadan Cairn. Player declares Long Grievous Siege on Ice-Orcs. He has Dale and Lake-Town in discard play, but other eligible cards are in his Location Deck. Hazard player respond with Chocking Shadows on Lossadan Cairn, that at resolution changes it* to . At resolution of Long Grievous Siege, Ice-Orcs are not playable at player's copy of Lossadan Cairn.

Question:
What counts for purposes of determining playability of Ice-Orcs?
a) Current type of player's sites in play?
b) Or maybe fact that Ice-Orcs are normally playable at opponent version not in play (or actually playable at version in play) is sufficient to consider Ice-Orcs playable at site in region Forochel?

Answer is important also for hazards like No Escape from My Magic, or Trouble on All Borders. For that cards question may be also:
c) which player's sites in play cunt for purposes determing of playability of Ice-Orcs?
[I think that it is valid question only if (a) is correct]



*) strictly speaking causes treating site as

[Bandobras Took]

I gave up on trying to make sense of Long Grievous Siege years ago.

[Konrad Klar]

Now I think that quote in first post may be a bit misleading.
Thread is more about Ice-Orcs than about Long Grievous Siege.