
Let me guess, bratty saint was called "an ugly/plain gurl" in her past life, or was rejected because someone else was prettier. That's why she just "wants to be pretty".
And studying was the thing forced upon her but she never got good grades, so now she doesn't want to study at all.
Now treating other people like shit was because that was how others looked/treated her before.
She can be vain all she wants, but if she's treating others because she can without any repercussions due to her looks, she can get kicked by a horse and I'll rejoice. Screw her backstory.

I'm thinking the bakery owner, Michelle, is somehow connected to "L".
She gave Fii the one week break without any reason and called it an "intuition". The priest Jake, also exhibited fear after hearing the bakery's name (ch14).
And "L" has to be someone old enough to speak about a prophecy regarding a royal baby.
Her friends' names are pretty accurate in the setting (Mini - small, Naka - middle, Oo - big).
That's just cute