[@Major Ursa]

to answer your question?

Amarante:
-Boss Battle/Genocide Boss
-Mini Plot/Main Plot/Dateable

Shadow:
- Mini Boss Battle/Hardmode Boss/Genocide boss (depending on the way you decide to play Genocide, Shadow can become a Hardmode Boss)
-Mini Plot/Main Plot/other purpose

Shrubmarine
-other purpose
-Mini Plot/Other purpose/Datable

Xarina Morelli
HUMAN.