There is just no way they could get proper sound quality for songs on location.
Galavant did live singing on location, according to several people who worked on the show. The way it worked was they’d record demos in the studio, and then sing live on camera with earpieces. Although they would mix between the studio and live takes to get the most optimal performances. I imagine OUAT will go the full studio recording followed by lip syncing route, though.
[adrotate group="5"]