Let me ask something, since it's been years since I've played BG. I remember that Oublek gets upset if you take Greywolf's reward when you first speak to him, and he will hold back a future reward as punishment. What happens if you kill Greywolf BEFORE talking to Oublek? Since Grey will now never show up to claim his pay from Oublek, is it possible to get Grey's pay AND still get the two rewards for completed missions? If not, would it be possible to include it? I hardly think whatever few coins you get by impersonating Grey would be game-breaking. As an extra, if you wanted, you could include a skill check or charm option or something of the like on Oublek where you take Grey's coin yet manage to sweet talk Oublek so that he doesn't withhold future pay from you for lying to him.
Another question I have is why there are two emeralds, since it seems to be causing a tremendous amount of extra writing on your part? Instead of having two items of one emerald each, why not have a single item called 'pair of emeralds'? This would give you your unique item, would reduce the coding and scripting and dialogue options you have to deal with (more text = more chance of bugs), and would save room in your inventory. I mean, all of this... gah !
when the player picks prism's pockets:
prism needs to cover the following possibilities
left gem taken, right gem in hand -- player has left gem
left gem taken, right gem in hand -- player stashed/sold left gem
left gem taken, right gem in hand -- player turned in left gem for bounty
right gem taken, left gem in hand -- player has left gem
right gem taken, left gem in hand -- player stashed/sold left gem
right gem taken, left gem in hand -- player turned in left gem for bounty
left gem taken, right gem taken -- player has both gems
left gem taken, right gem taken -- player stashed/sold both gems
left gem taken, right gem taken -- player turned them in for bounty
and i suppose out of fullness sake he should notice the following tho the statements don't have to be the same.
left gem taken, right gem taken -- player has left gem, stashed/sold right gem
left gem taken, right gem taken -- player has left gem, turned in right gem for bounty
left gem taken, right gem taken -- player has right gem, stashed/sold left gem
left gem taken, right gem taken -- player has right gem, turned in left gem for bounty
That's a heck of a lot of, IMHO, unnecessary work. If you replace the two items with one item, I would think things would be much easier for you. But I'm not a coder, so I don't know.
I do think though that there's very little reason for anyone involved in this situation to split up the gems. Prism wants both gems to finish his work, not one. When he dies, he drops both gems, not one. Greywolf will let you leave in exchange for both gems, not one. Oublek wants both gems returned, not one. The owner wants both gems returned, not one. If you decide to sell them, you are going to sell both of them, not one. So to me, it seems fine to replace the two items with one. Whip up a simple icon, call it 'two emeralds' or 'pair of emeralds' or "Prism's emeralds' or whatever, and you're done.