I can prove Kuja > Neo Exdeath easily.

Kuja destroyed a planet.

Exdeath and the Void never did that.

Nothing says they could either.

So, Kuja > him in power.

As for Ultimecia...that scan makes no sense. She is mixing past, present and future together through Time Compression. No one ever says she is absorbing anything. And also thery never say universe or existence in any of the dialogue. They just say "world" ie. the planet. No one brings up the universe or all of existence at all. Just their world.

And if we're talking fights...Ultimecia dies hard.