Personally, I'd merge the functions of
I think this makes sense if we're approaching them more as characters and not bodies built around a gimmick (oh, Transformers). Their "personalities" in the Covenant book are so generic as to be interchangeable and overlapping anyway, and it's unsurprising that there was this attempt to have a Zodiac sign-like "polarity" thing because Zodiac signs sound similarly interchangeable. Oh, a Taurus can be hot-tempered? Can't anyone?
Sure, it makes sense to tie the notion of having a group be all of the firsts (of insert gimmick here) with that group being the first of the race anyway. Still, how much more meat is on that bone? You could instead tell a dozen or so stories of individual historical icons (even if they became iconic after the fact for happening to be the first), but here it's just a cluster of bodies existing to be the first for its own sake.
If we must have a 13 (or equivalent), I'd rather them turn out to have all been normal Cybertronians from the early, lost to history days of Cyberton. Any mystical abilities or origins are just legends that have grown up around their relatively humble actual stories. Maybe most of them are actually from different (though still ancient) time periods and never even interacted.
Basically the way there was a real King Arthur in what is now England, but the stories that we tell about him today bear almost no similarity to him.
I like this idea. Like what Barber did but no Shockwave at the center of everything. It might even still be interesting to have the artifacts and firstnesses, just emerging in a less contrived manner.
Or let's try and have it both ways. There's an actual pantheon of Thirteen, or Seven, whatever, at the dawn of Cybertronian creation. But absolutely nothing is known about them other than the names the descendants give them, and the belief system that has been built up around them because of the artifacts attributed to them. (May also want to rein in these artifacts a little bit so they don't have to dance around how they work so much, to keep from breaking the plot more than they do.)
The ones that become characters and that we associate with the names (and who may become legends to our present-day bots) are ordinary Cybertronians from later on, spread out across history, who take on the names or are called them by their people. Your King Arthurs, your Robin Hoods.