Unidentified gunner
This person, who identifies as male, was a gunner for the Rebel Alliance. Serving under the command of Captain Miara Larte, he was not on Alderaan, his homeworld, when it suffered destruction. During the Royal Award Ceremony in 0 ABY, he was at the Great Temple located on Yavin 4.
Behind the scenes
Miara mentions in "By Whatever Sun" that the gunner's name is something along the lines of 'Hester, Heattens, or a similar name'.