What’s their role among their relations? Do they consider others family?

Put bluntly? He best serves as the mediator of a group. Distant from others, but always there when needed. Always the neutral factor that tries to help out others for their benefit. He’s not family, no. Just a guardian. Someone to be there when you need help. When you need a hand to pull you back up.

When you need hope. That is his role. 

How do they handle contact? Is their personal bubble big?

Seeing a familiar face in the Hive City is a surprising yet welcome turn of events. "Boy! So you've turned up in this strange city as well?" How long it has been since he's last seen him isn't clear, but Rider notices Waver's height right away.