A Wiki would be good. So we don't have the rewrite everything, it would be simplest to port over all the character sheets lying around. We could then identify holes in the information. Linking relevant posts would be something to consider.

Additionally, it should be easily accessible by everyone to edit and read. If it requires pushing all the information through a single person, or some convoluted setup, it will likely fail.

There are plenty of online wikias. I'm sure one of them would be simple enough to use.