Handling bibliographies with many coauthors

You might want to consider to use Mendeley http://www.mendeley.com/, which is in essence a bibliography manager that is -- in my opinion easy to use. You can also share (partial) libraries, and collections can be exported (and imported) to BibTeX.

The program Mendeley is free, and quite good in organizing even your existing library of PDF articles. It should be intuitive enough for your collaborators to use, and is available for most platforms (MAC / Linux / Windows)

I'd recommend using a central reference database that everyone can add references to and which generates unique citation keys. In particular, I'd recommend refbase. I have a slightly modified version of it (see below) in which I've changed the field names to something a little more useful for mathematicians (it was designed by geologists) and in which I've added automatic importers for the arXiv and MathSciNet: so simply specifying an arXiv id or an MR number is enough for it to go and fetch the data needed.

This approach would also mean that you could put off the BibTeX/AMSRefs choice for a while (assuming that both use \cite{ref} in the text).

My modified version of refbase is available on github. (NB the comments below refer to an earlier repository, not the github one.)