Finney:

-Gwen obviously that girl boss is his only sibling

Robin:

-Has a little sister that is like 3 or 4

Vance:

-Has an older brother that moved out a while ago he's like 23

Bruce:

-Younger sister Amy Gwen's age

Billy:

-Older sisters probably 1 or 2 they are like 3 or 4 years older than him