1. Can't speak too much for others, but I'm pretty interested in this general area, given that the group doesn't get too large.
2. Semi-serious? Not so much as to throw all jokes and bullshittery out but enough to enforce some measure of quality/schedule
3. I am leaning towards one of the side characters, but I don't have particularily strong preferances one way or the other
4. I would mostly depend on the GM to provide the plot, but I would want to build a character arc for myself. That being said, collaboration between the two is pretty important so the whole thing doesn't feel contrived.
5. I often see people keep OOC on Discord and the actual RP on the site, and I think it works well enough for me.