OK, last bump with a few background infos:
So Denmark, Norway and Sweden were elective monarchies at the time. They were almost running out of heirs of the ancient Norse royal families. I haven`t scanned the entire family trees several generations back, primarily because the knowledge I´m really lacking is which families were how powerful at around 1459, say (which was the year of Erik`s death IOTL) and without that knowledge, it´s rather pointless to suggest this or that remote heir.
Pommerania was a hereditary fief, but it was disputed just around this time, whose: the Holy Roman Empire`s directly, or Brandenburg`s maybe? Here, heirs through Erik`s niece Sophie were alive.