the "green eyes" line. The emphasis was on the "blue eyes" part in that moment because the blue eyes of the Wights and White Walkers were especially emphasized over the course of the battle. It was never said Arya would kill an important person of each eye color and that conversation included confirmation that Arya has already shut many eyes of different colors. Maybe I'm wrong but at this point I'm feeling even more confident that these theories (Arya shutting green eyes means Cersei, Bran was pulling the strings during the Battle of Winterfell thru warging, Bran is the Lord of Light or becomes reborn as the Night King, etc.) are just fans trying to ascribe more meaning to all these different aspects of the show because it's nobody wants to accept that the writing has gotten so incredibly sloppy.