For anyone who implements an AI, any justification for including other members of humanity in their CEV calculation is valid iff their CEV would specify that anyway.

YES! CEV is altruism inclusive. For some reason this is often really hard to make people understand that the altruis belongs inside the CEV calculation while the compromise-for-instrumental-purposes goes on the outside.

So, the rational course of action for anyone implementing an AI is to simply use their own CEV. If that CEV specifies to consider the CEV of other members of humanity then so be it.

This is true all else being equal. (The 'all else' being specifically that you are just as likely to succeed in creating FAI<CEV<self>> as you are in creating FAI<CEV<whatever>>.)