I'm the lead on the Moderator Council project - it's still in development but you've asked a good question here and I might as well share what I can to address your specific concerns.
there has been mounting suspense regarding formation of a group of user representatives to discuss ongoing issues having to do the the SO platform.
Not "a group". Several. From the original announcement, we mentioned two separate projects - "Better Mechanisms for Community Feedback" with the solution:
We’ll share regular updates about what we learn through our research, as well as create a new working group of users that we’ll lean on for regular feedback. This working group will be made up of a diverse group of folks excited to see Stack Overflow grow.
And we also mentioned "Creating a Moderator Advisory Group" with the solution:
To address the challenges we identified, we’re putting together a moderator advisory team drawn from our 550 existing moderators (folks who volunteer their time and donate their knowledge and leadership to the community): a small, self-replacing council of moderators who will be tasked with keeping our moderation guidance and methods up-to-date, along with ad-hoc working groups of moderators to work on specific initiatives as needed.
These are still two separate groups! I don't have a lot of details about the former group at this point in time but the moderator council is still what we originally described. The primary purpose is to make sure that the needs of the moderators are met, either in tooling, moderator guidance and policy, or making sure the moderators have an avenue to bring concerns and needs of their sites to the company.
The vision I have is that this council and its committees will be entirely moderator-run - but the final makeup is going to be up to the moderators. If they feel like having a seat for a non-mod is necessary, we'll talk about it. But the council is not dozens of people large. The current plan is about 7-9 people with subject-focused committees of moderators working on specific projects. And, well... if the committees feel like doing some/all of their work on MSE so that non-moderators can participate is the right choice, I'm fine with that.
While we will also be talking to our moderators as a valuable subset of our communities, they are not the only group and acting as a group of testers for all future projects would be limiting - moderators have special access and tools. They are also expert users of our sites, so for projects that need the PoV of a newer user or even an expert reviewer (many mods don't use review much because their votes are binding), we can't rely on moderators for this - we must talk to other groups of users, and we will.
I hope this helps shed a bit of light on the goals of the Moderator Council. You're correct that moderators weren't elected for some of the work we're going to be doing moving forward but the council is a great opportunity for mods who want to help innovate what moderation and community building looks like on Stack Exchange as we move forward.