Photos with faces in them are almost always more engaging than photos without.
Not a hard and fast rule in all cases, obviously, but in most cases if there's question in a given situation "face or no face?" the face will result in the more arresting image.
Did your father-in-law attend a university? If so they might be interested in acquiring his work for their archives/permanent collection. You could also reach out to the university gallery director and see if they'd be interested in an exhibit of the Cambodia collection.
Can't. OP gave the band the photos, so OP has zero rights as long as the band credited them in their communication with the paper. The band could complain, but OP could not.