In Rogue One we hear:

That the rebels wouldn't officially support the attack to retrieve the Death Star plans because a majority of the council did not vote in favor of it. Well who is on this council anyways? Whoever can crowd their way to the edge of the table? Presumably not, but how are the council members chosen then? Is the council we see in Rogue One the same council that persists during the original trilogy?

I can't recall if there was even any explicit use of the word council in the original trilogy let alone an expounding on its members.