It is VERY IMPORTANT to cast strong singer/dancer/actors, get the music supervisor to clear the music and bring in the musical director to arrange the singing leads, solos and backing vocals. IT IS IMPERITIVE THAT REHEARSALS ARE DONE WELL IN ADVANCE OF FILMING. THE MUSICAL ELEMENTS SHOULD BE APPROACHED AS THEATRE REHEARSALS.
Bring the choreographer to give movement to the staging of the choirs. This is the big part of my job. As they rehearse, I will be working with my camera man to pre light and get the camera moves well rehearsed. We will need stand ins who have experiance of dance so we don't waste time. I am aware this isn't Broadway but for the sake of liveliness, I anticipate some of the choir sequences to have a fair amount of movement.
We will work on set with pre-recorded playback. I suggest we shoot the dialogue first, mark the song, get to the end of the dialogue in each scene. Then go back and cover the songs as inserts.
We have to get on and pick all the songs to feature; secure usage rights from the original artists; rearrange them in a show choir style; work out which members of the cast will be singing leads, solos and backing vocals; record the cast singing the songs; rehearse the actors moves, bring in tech heads of department into rehearsals, then film the cast performing them as part of the narrative action.
Equally, all of the cast understand the narrative importance of making sure the musical performances hit the right note.
This is top-to-bottom detail – narrative, musical, visual – that will make Xmas Carol such fun Christmas spirited, entertaining viewing.