I would like to double check with the CoP, my understanding of the last paragraph of 2.5.1 "Elections & Eligibility"
"All Core Circle Members are eligible for election" for me does not mean that ONLY Core Circle Members are eligible, but it means that everyone who is a Core Circle Members, even if temporarily, has the right to be elected. It does NOT exclude non-Core Circle Members from the election.
Furthermore, 3.3.1 "Attendance" is also talking about the possibility that the Facilitator and the Secretary are not Core Circle Members. That does reinforce my understanding in that way.
As a rule of thumb, I think in general that might not be a great idea to have a Rep Link that is not a "stable" core circle member, because of the need of understanding of the tensions of the other members. However, I do not see why a Facilitator or a Secretary should be stable members of the circle if some external people are seen as the best fit for those roles. And actually, even for a Rep Link, the same reasoning should apply.
And there is always the possibility to object during the Integrative Election Process or to call for other elections if needed.
Please let me know your understanding about that.