Backing this, I've found prompts for being able to character change on her as well as her voice actions in combat (no text, just prompts for them).
Something like: "LUNA_CCHANGE_.....", "LUNA_DMG..", "LUNA_CURE...", etc in the voice files (Basically the things she will say when she theoretically changes to being playable, gets hurt, heals people, etc). The 4 bros look exactly like this as well so it definitely looks like something.