Not that anon but I think they are kind of foils of eachother, in terms of their personalities, and how they navigate through life. They are kind of opposite paths our MC could have taken, in a way. Different ways that loners and outsiders deal with their situation. I could elaborate more, but in brief:
introverted and inexpressive but very direct and tactless, doesn't bother trying to fit in and barely contemplates how their behavior comes across to others.
Outgoing and cheery, inwardly outside the norm but self-aware enough to hide their true self, carefully constructing their persona to be 'normal'.
I know I went through versions of these at different stages of my life.