Genshin characters from short clues (V.6.6)

If you mean why mushrooms, I chose them because Tighnari's demo shows him studying mushrooms in the rainforest. He also often speaks about people not be careful with mushrooms. Oh, and when we first meet him in the game, he is also lecturing someone about mushrooms.

I actually considered changing them, but then tanuki also fits very well for Sayu and I decided just keep them.

I disagree, Columbina is literally called MOON Goddess. It is so big part of her lore that I won't change it.

And big part of Barbara's story is that she sings to her patients. She even got her Vision when she sang a whole night to help sick kid's pain. She is also called Idol of Teyvat and idols sing.