Signing Day has no significance to EE's except to confirm their future teammates. As you noted they are already student-athletes by then. They will be doing the same thing the other student athletes do at that time of year, classwork, conditioning, and participating in non-supervised (no coaches per NCAA regs) "team" workouts.
JC will pick up his playbook as soon as he is a student. I have no doubt JC and company (brothers, private QB coach, et al) have long ago broken down all the plays in the ND games of the past two seasons and compiled their own ND primer playbook. Those plays have been diagrammed, annotated, and are already in his mental database. They've noted the situations and the formations and how the defenses defended against them. They've looked at why the successful ones worked and why others didn't. He's studied the reads Brady and his receivers saw as much as those game tapes allow.
With all the prep this kid has had in getting this far I seriously doubt he's sitting around waiting. He'll have a learning curve but he's not starting out at the bottom. He'll be the most prepared freshman athlete stepping on the field his first day since Joey Getherall.
