Cool idea but I think there are some license issues with movie characters and that's why we don't have them. (pretty sure that's why dreamworld Hinata was changed back in the day)

EDIT That being said there are some leaks that Toneri might be coming for Chinese version so who knows [I understand that leaks don't mean it's confirmed]

You are right my bad, completly forgot that Sora arc was filler instead of a movie . 100% viable then and since that's the case kind of shame they didn't release them already.