What sort of balance between posed shots and candids should I get? What about the trend of photojournalism?
This is also a matter of taste, combined with necessity. Great wedding photography can be done with no formal posed photographs at all (wedding photojournalism). But, there may be many people and combinations of guests that will never be captured unless the photographer deliberately gathers them in one spot for a picture. (Whether the picture looks posed or natural depends on the photographer.) When planning with your photographer, draw up a list of “must get” photos, such as college roommates, kids from your old neighborhood, a four generation picture, and so on. If you want a large catalog of specified photographs, then expect your photographer to spend more time doing those, and less time doing candids and wedding photojournalism.