Suppose I initiate a military challenge with Raider from Orkwood:

1) Can I naval in Victarion Greyjoy for the purposes of triggering the agenda? Even though his strength is not counted, he still counts as participating in the challenge with zero strength, correct?

2) In the (unlikely?) event that the answer to the above is no, I presume that Fleet from Pyke can be used as a naval entrant as it would remove Raider from Orkwood from the challenge?

Thanks very much for the assistance guys!

As you suspected, you can naval in a character and succesfully trigger Black Sails (provided you win) and, in the case of Victarion, raise claim. A character doesn't have to count their strength to be participating!

Thanks a lot pal!