Emilie’s not a big fan of singing. I’m sure I read somewhere that on Lost she really had to be persuaded to sing a couple of lines. If that is indeed true, then I can’t see Belle singing an entire song.
Bobby is the obvious one. He’s done singing for a role before but Rumple just doesn’t seem like the singing type.
This episode is going to be compared to Buffy’s musical episode and it is going to lose. OUAT lacks the character consistency that Buffy had.