Material parameter doesn't change on one of the clients (sometimes)

Corrupt or otherwise empty save file?

Also, logic wise I would do:

Client load > set profile > send to server.
Server registers.
(Server sends to client new player join or Client queries server that one player joined), client spawns in appropriate character(s) with server given peofile.

Not sure thats what you got from what I see up there.
The point is that someone has to be in an autoritative position to tell all clients what color is what - else client hacks are possible (like making the material transparent for instance).