This is a great question, to which there is no solid answer. Stories sometimes "flip" gender roles, so it is not impossible that they two could be historically/genetically related. On the other hand, they may be, simply, striking similar chords. Distinguishing the one from the other - particularly when dealing with close proximity - may be impossible.

I have wondered if Tale Type 313, which is behind Jason's abduction of Medea - and which is spread throughout Europe - is not behind the Celtic complex of stories that manifest in Diarmuid and Grainne, Tristan and Isolde, and Lancelot and Guinevere. In these stories, the woman often plays the dominant role, directing the king's hero to leave with her. Are these related to Type 313? Perhaps, or maybe they merely play with the same themes. My inclination is to see these as related. I don't know enough about the corpse bride to evaluate her relationship to the betrothed who dies in a distant land and then returns to the woman who promised to marry him. But that is a great question!