A significant part of the past discussion here and in other singularity-related forums has been about verifying that our values are in fact compatible in this way. This is a necessary condition for community efforts.

Not so much. Multiple FAIs of different values (cooperating in one world) are equivalent to one FAI of amalgamated values, so a community effort can be predicated on everyone getting their share (and, of course, that includes altruistic aspects of each person's preference). See also Bayesians vs. Barbarians for an idea of when it would make sense to do something CEV-ish without an explicitly enforced contract.