Happy to hear you're feeling better, RossN.
In regards to the current situation, if we're not going to try something why are we even here? For all we know, one of the prisoners might be Wadim and even if not, they probably have information we don't. Is there anything we gain by sitting a bit longer and doing nothing or do we just avoid the risk involved in making an attempt?
They're not going to scatter from a few arrows. They outnumber us 10 to 1. Trying to win in a straight fight is not going to happen, which is why I say distraction to empty the camp and stealth. For that, I don't think it's strictly necessary to kill the chieftain (just piss him off) and even if it is, it doesn't take five PCs and a handful of NPCs worth of shots to kill a goblin. Two solid hits, three to be safe would be enough. We're got a good height advantage and if we do it right, most likely the benefit of aiming and a surprise round.
A mind game alone wouldn't. Being under direct attack with the mind game making the threat seem bigger than it really is could work. They're not going to sit around and do nothing if one of us puts an arrow/bolt/bullet between their chieftain's eyes. They're going to realize they're going to attack and then it's fight or flight. I doubt it's flight, but if so... Well, we win. If it's fight, then we spend a couple of rounds taking pot shots while they try to regain order and move out to engage and then leg it before they can actually get to us.