The Dia De Los Muertos sequence was filmed in two parts. Hollow, the song performed by The Weeping Woman (Wendy Rule) was filmed on the first day of filming as it was her only day of availability. The rest of the party was filmed at the end of the shoot. Both nights were full moons.
The version of You'll Never Walk Alone that plays softly on the piano in the final scene was recorded by director, Nicholas Verso, on his iPhone at the house he was living at for the shoot. He only recorded one take, playing by ear, assuming it would be a temp recording and a proper version would be recorded later. But in post, everyone agreed the slightly-off, awkward playing suited the tone and it was used in the mix.
The film originally featured a scene where Romany performs Tori Amos' Caught A Lite Sneeze.
Hollow, the song featured in the Dia De Los Muertos sequence, was written by Wendy Rule who performs the song. It was originally written as part of an operetta about Demeter and Persephone with the song detailing Demeter's grief at losing a child. Wendy learned Spanish for the film in order to translate the song and sing it correctly.
Originally the character of Jonah was meant to be linked to Jonah from Verso's short film, The Last Time I Saw Richard (and there were references to events from that film in Boys In The Trees) as they were written at the same time. The making of the short, however, pushed both films into different directions. This, combined with Toby growing up and now being too old to play the character, meant it was necessary to recast. So now the two Jonahs are meant to be viewed as two parallel characters.