I think we maybe disagree on what truly constitutes a dangling thread.
If the final issue of, say, IRON MAN had ended with Tony Stark being thrown into a volcano, and we didn’t resolve that moment, then that would be a legitimate dangler.
But asking about relatively obscure stories from years ago and how they work in concert with SECRET WARS does not, to me, constitute a dangler. New information always overrides old information.
So I’m not terribly worried about questions like, “Weren’t those guys immortal?” Maybe so under ordinary circumstances–but when you’ve wiped out literally everything, not so much. Surely there were immortal beings in the Universe that existed before this one, the one that Galactus comes from–and those guys all seem to be gone, too.