The reason Hamill and Vonn Sydow are wearing the same shirt is a subtle hint to the plot Episode 7 and the following movies. Ep 7’s plot will be mainly centralized in a flashback from Luke’s POV. The Empire been biding their time, returning to full power and then execute an attack on Coruscant, leaving all but Luke & R2 dead (yep, even 3PO bites it). Then 70 years later, it is still played from Lukes POV now played by Von Sydow. He has spent the past 7 decades searching for force adept Jedi to train and launch a counterstrike against the Empire. True Story Bro.