"He was a lot of things to me" "The only conclusion was love"
I wonder if David’s brother James could make an appearance, too? Would be the easiest dead character to bring back, considering Josh plays both.
And James was a villain (of the mundane, non magical variety) so yeah, I’m sure he’s there too. If King George hasn’t been fed since S2, then he might be there as well.
On the whole, I’d expect to see: Pan (or Malcolm depending on Robbie’s availability), the Snow Queen, Cruella, King George, James…