Welcome to the world of publishing. Or rather, cross-platform publishing.
not helping Ahz...
Really, who's going to take the lead in this and what is the preferred way to go?
My personal favourite: open document accessible to all, let everyone cram in their part until you have a (very likely very ugly) base or 0 version, with different styles and layout. Then take the doc off-line, do the layout and general editing. Put it back and from then on use some method of control on the submissions, e.g. limit editors or use some track changes method.
The reason I like this is because you can get a 0 version pretty fast and even if you do it 'the right way' from the start, you'll have to do the layout later on anyway.
If we we're to take that strategy then the first step is just blatantly copy paste Wiki articles straight into the doc.
Scriptminion has a good point though, what is