@NotVerySmart - One could argue an EA acceptance is wasted if one applies to a school that would accept your RD anyway. Likewise, an RD rejection at a school that would have accepted you SCEA is a missed opportunity (note: evidence suggest that SCEA applicants have much better chances of getting into HYP).
If your’e interested in HYP, the challenge will be determining whether you are possibly in one of these groups, and how maximize your odds of acceptance.
My gut feeling is that a US dual national living abroad with your academic credentials and english language skills is likely to get into at least one of HYPS - in fact I would be extremely surprised if you did not. If one of these schools appeals to you, then you might consider maximizing your chances by applying SCEA.