A basic description of the character – about as useful as “Han Solo, but young” – was created, agencies listed the role as a situation vacant and actors started to get in line. I don’t know if anybody has read for the role yet, but if they have, it was under an even heavier veil of secrecy than the saga casting is hiding. My best guess is that the filmmakers are very, very early in the process and just rounding up some candidates for now.
Pity the casting agents: Finding a “young Harrison Ford” can’t be the easiest job in Hollywood. The first spinoff, whether it features Han or not, is aiming for a 2016 release.