The press notes accompanying “Tótem,” the new film from Mexican director Lila Avilés, describe it as a “choral film.” As a literary turn of phrase, it’s better suited for Ms. Avilés’s movie than, say, “ensemble piece.” The latter presupposes a group of individual actors who inhabit a story with equal emphasis; “choral” suggests something blended and organic, a whole in which parts aren’t summed up so much as made inviolable.