The mitigation you get from it is based on the ratio between your vitality and your level. If your vitality is say, half or double your level, you get half/double the default mitigation from it. It also unlocks arguably the best traits, so even 5-10 will be a major boon to survivability.Is vitality just a worthless stat outside of events if it's not equal to your level? Also I'm only on the third area(The Yamabiko character having green hair is a refrence to the Touhou character right or was that just a weirdly precise coincidence?) but after the prologue bit does Sarah just never get her Sweater outfit if you didn't choose her during the home portion?
I know that 2hu girl exists but idk a whole lot about her, to my knowledge Maya has a different personality, skin color, outfit, and temperament than her. She's just been an idea I had rolling around in my head for a while and wanted to turn into a character. Small, darker-skinned, green-haired girls (including dog girls) seems to be a more common trope than I had realized initially lol.
On the sweater - that is... a fair question. I THOUGHT I set it up to update if not, but if it hasn't been updated for you I may have done something wrong. If you talk to her in camp, does she not have the sweater?