In the absence of any evidence either way I'd be quite happy to accept the early Swedish version on face value and use it as the earliest known text. It has cohesion and is not overelaborated. It has all the hallmarks of a traditional North European ballad as set down by Child. As we know Scandinavian balladry in general was much much stronger and well-established in the 16th century than here in Britain, I'd be inclined to give it prime status (as with Child's A versions) with the proviso that there were probably earlier versions in Scandinavia.

I think things will become clearer when you have all your versions together and can compare all texts.

Personally I think Taylor is at most a distraction for reasons I've given earlier.