Bump. And I got Wolf's okay to do it.

Now since Trema was mentioned, I think it needs to be talked about because, unlike most of the Final Boss vs. Superboss debates, it has some substance.

We find this substance in a cutscene and text.
First, the cutscene:
YouTube - Trema Battle Part 2

As you can see, Trema canonically destroys Paragon right there in the cutscene. And pretty easily too I might add.

Now, what do we know of Paragon?

1. It's Lord Zaon, the spirit who made the first Final Aeon to defeat Sin.
2. The text I mentioned earlier is the Scan you can perform on Paragon:
"The strongest fiend of all time. According to the little data available it has the power to rend the heavens and sunder the earth."

In short, Trema just owned the strongest fiend ever who was made from the spirit of the same man who was once a Final Aeon.

I would say that Trema could very well be near the level of power of Braska's Final Aeon (the real final boss of FFX) or Vegnagun.

On the note of FFXII, isn't The Undying:
A. Infused with a good majority of the Sun Cryst's power
and
B. Fused with Venat?

Now considering the power of the Occuria and the fact a small piece of the Cryst can blow a city and its surroundings to Hell, I would thik he's stronger than the optional bosses.