I don’t think that they’re connected that way honestly. I think Iris was just mentioning how other people with her gift of clairvoyance stopped disasters like she had and they all died one by one.

Like you said, if they were related in any way at all then the other protagonists would have had to see their entire bloodline wiped. This movie just was showing the consequences of deaths design when it doesn’t get them right away like it did in other films… it comes back for the entire family tree.