Hey, adickus! I am glad you liked the game!
About your questions:
1 No, state of mind can change, but there are a few specific choices that can alter it( Mostly, if Luna acts out of character). For example: if Luna is a badass or a hero and refuses Vera's challenge -> state of mind increases.
2 In update 0.26 on the hero route, Luna will look different (taller, blonde), on the sub route, I will add a few piercings (nose, nipples). No changes on the badass route.