Thanks for posting the question. There's some explanation on the profile in the Disputed Origins section, and more in the "More research needed" section, which I just moved up so it was more visible.
There should be better sources on there, but if the information is correct it sounds like Edmund's son Henry died without issue, probably young, and so therefore couldn't be the immigrant.
Also looking at Henry's bio, he was a butcher...which would not be likely if he came from an aristocratic family. I'm guessing that the story of his parents came from a 19th century/early 20th century genealogy. It was typical to try to connect American immigrants to noble origins, often selecting a child who had died without issue as the connecting point. Unfortunately, people can become quite attached to their pedigrees and craft stories that they were disowned and written out of the family history, just to maintain the noble connection.
I've added some potential sources for information on Edmund's genealogy if you want to double check, but I think you'd likely be researching someone else's family (which can be fun!).
On another note...have you ever looked at some of the court records for Henry. Some of these may be for his son, I didn't delve to deep, but it gives you a little more insight into his life in Salem.
