I've given brief descriptions of each of the party members.
Ambrosia, Julian's daughter, takes after her father in being a physical and martial powerhouse. It's not clear where she got her predilection for powering cross-Shadow nanotechnology with the Pattern in her own blood. Ambrosia is usually an NPC, but has been handed to an out-of-towner as needed.
Jerome, Fiona's son, is laconic and suspicious. He is usually in the company of Bucephalus, a giant, shadow-walking tiger.
Katsushiro is an Agent of the Crown and a Trump artist.
Maris, Bleys' son, is a militant who has spent many years in a Japanese-themed Shadow.
Ferris is a self-taught Trump artist who became embroiled in Amber business when he became the agent of an elder dragon.
McSweet, some bastard child of Amber, is a musician. He had a band on Shadow Earth before it was destroyed.