Your first paragraph seems like a technical issue that may or may not apply in practice, not something that really gets at the heart of CEV. For the second paragraph, I guess I was thinking of the limiting case of there being a single creator of the FAI. With groups, it presumably depends on the extent to which you believe (or can measure) that the average individual from some other group is a better match for your CEV than your FAI co-workers are. But if that's the case then those co-workers will want to include different groups of their own!

I do agree that political issues may be very important in practice though - for example, "we'll fund you only if you include such-and-such people's CEV".