In my case, I asked our openSUSE Board for being allowed to be a Community Representative in this decision making process. I would suggest you to do that equal with the Fedora Council.
Hi Sarah. I would certainly support having someone from the S390x SIG being on such a working group.
Maybe I'm misunderstanding, but I don't think that person would necessarily need to be a Fedora Council member, and indeed it's probably better to empower someone closer to the work.
Does the "Community Working Group" need something formal from us?