The distinction I'm thinking of is their finished work, like and illustration or a story or whatever. Clearly the materials that the work draws upon are CWBP 2 property (like the world map, names, histories, etc. sort of like brushes or fonts I suppose) but the work itself should need final approval of the person who made it before the board can release it. This doesn't mean they have a say in work derived from theirs, as it is part of the CWBP 2, it only means that CWBP 2 can't make commercial moves with their specific creations without them. Meaning they can't be arbitrarily cut out of the loop and screwed. They can also make a deceleration relinquishing their right of final approval which would of course give CWBP Copyright board freedom to manage it as they wish.

To the Board: No the board decides on all matters regarding copyright with whoever decides to participate (ie vote), regardless of whether or not they had a hand in that particular element. Undoubtedly it will tend to be those involved that are most interested in that particular vote, but it is not limited.