Disagree with the star level base tier arguments, at least in early show. The shockwave provided is quite clearly a gag feat. Just a few minutes prior, Samukai, a foe clearly superior to the ninja at this time, was killed by their combined power, and Lord Garmadon himself confirmed even he could not handle all their power. It would be beyond inconsistent for the ninja to be superior to Garmadon, especially at this point, and the weapons are clearly not expelling all their power into that measly little shockwave. Massively inconsistent with established story and much easier to explain as simply not the full power of the weapons hitting them there, as the full power of the weapons would kill them on the spot like it did to Samukai or would have to Garmadon.
Garmadon and Wu confirming nobody can handle all their power at the time and Samukai going badda boom
I actually do agree with Golden Power Lloyd scaling to the weapons, so no argument there, though the others don't scale to him. Rebooted makes it crystal clear that at this point only the Overlord can survive the weapons as they are now, and everyone who touches them dies. That random Nindroid, those weird bugs, and even in the finale, Zane. Yes, he didn't immediately die, but he was expelling as much excess energy as possible to stall the inevitable and still went up like a roman candle in the end. This also shuts down the idea that the ninja would scale after Lloyd gave them powers, as Zane quite literally got killed by the weapons after getting that buff. None of the base tier ninjas scale at this time.
Following Rebooted there aren't any Golden Weapon level threats barring the Preeminent, which nobody scales to at this time as they won via the biggest weak spot abuse of all time and a massively lucky one-off power boost from Nya.
Nadakhan's feat of lifting and sustaining his new "Djinnjago" could likely be calced and used for base tier scaling though, I could see that getting above their current town level and being solid scaling. Would need to get a number on it first of course.
Time Twins don't have much of anything outside of cool hax.
Season 8 is where you might be able to open the door on this scaling, hypothetically. I'm not sold yet but willing to hear your case on it, though Lloyd kinda got rocked by Garmadon in their duel. But I'd like to hear your case there.
If you do have something for Season 8 onward, I would suggest splitting ninja and base tier stuff into keys. Seasons 1-7 base tiers likely go to whatever Nadakhan gets off of the Djinnjago feat, and if you can pull off 4-C on Season 8 onwards that should get its own key. And so on from there, we already have era based keys for characters like Sonic anyway.
That said, this is my only major disagreement is with 4-C and you might be able to sell me on an era based key system. Agree with the Universal+ arguments and think Jay should also scale as there's no reason the others are suddenly above him now. Neutral on Low 1-C Source Dragon, will need to look it over later when I have time.