I would suggest, especially when players are coming from more co-operative games, to provide the group with a singular mission (recover this McGuffin from shadow) but have different Elder Amberites give different PCs sub-missions in secret, that may well drive the group apart.
For instance:
Fiona's son is told that the McGuffin is an item of great magical power, and it is too dangerous to trust to the others. Recover it for her.
Eric's daughter is informed by him that this McGuffin is an artefact of Oberon, is connected to a larger system of objects, and could shift the power. At all costs, do not trust Bley's son, because he will want the power for himself.
Corwin's daughter is told by him that this McGuffin is too dangerous to be brought to Amber and should be "lost" along the way.
Etc., etc., etc.
PCs will decide on their own if they want to uphold their parent's wishes, align with other PCs against their parents, or some combination therein. You set it up, it runs itself.
For setting inspiration I'd suggest the 1980s cartoon Visionaries: Knights of the Magical Light about post-apocalypse populated by knights, beholden to a wizard in a kind of magical arms-race. The premise is brilliant, and I've run a successful Amber game of it in the past.
//Panjumanju