I can explain some of these choices.

Kia and Amy (The two kimono girls) must have some combat experience because they arrived from the LOST LIBRARY. I feel like even if they do travel as a team they may encounter enemies like the Snow Bunny that requires that they can at least survive a battle.

The Galactic category is for "Higher beings". Beings that are in some way above reality. But you can see their entire size theoretically. Cosmic higher beings are so grand that what you see in game is merely a small part of them, a single victim or a single vessel of them.

Also I believe Noelle is only a "Good Warrior" because with her knowledge of it being real her snowgrave potential isn't there anymore.

Kris is in "Epic Warrior" because the Creativity Stat being Kris's (Has 5, there are 5 acts per enemy.) implies that Kris has the same Acting ability in universe. Also the chapter skipping feature implies there is a "Default" run Kris is capable of doing without you, thus Kris can beat the main routes without issues. And certain enemies are higher than Kris because Kris defeated them when they were part of a trio.

If you disagree or something feel free to tell me. (By the way Most regular NPCs would land in the regular category.)