Hahaha, my vote is for the white flying squirrel thingy.
So, I haven’t seen Frozen yet (I know, how that’s possible I don’t know) but I don’t necessarily think Anna has to be dead or anything…Rumple’s (at the time the urn would’ve been put in the vault, people can speculate if it is still the case) not the kind of guy who’s going to say “oh, ok, you were a threat but I see your love for your sister negates that, so let’s let bygones be bygones.” If Rumple perceived Elsa as a threat (for whatever reason) and he figures out a way to ‘bottle her up’, he’s going to do it. And this would fit in with the ‘misunderstood, not evil’ thought process. And if he bottled me up, I’d be pretty PO’d once I got out! So while the other Frozen characters may be in the present, or only flashbacks, I don’t necessarily see her sister’s death as being her only motivation for a possible desire for revenge or what have you. If she’s even the Big Bad, and not just a misdirect in the first place…