What you describe, pure jus sanguinas, breaks down exactly as you describe. Many people have a hard time separating family from nation.
How long was mother Cruz over in England with Husband #1? She ends up coming back to the US after her child - which she became pregnant with well after the divorce from Husband #1 - died from SIDS. Then she very soon after seems to have met Cruz, and they moved off to Canada, from ‘67 to ‘75, right?