What form does stellar iron take once the star it was formed in fails? Is it a gas? Small solids? Individual atoms?

Is that meant to be good? I always chuckle when people make these kind of statements. Is the association to cosmic objects meant to make you feel better about something? I personally don't find stardust particularly interesting. The fundamental forces of nature on the other hand are much more appealing to me.

https://www.iaea.org/newscenter/news/meet-oklo-the-earths-tw...

But there's another source out there that we can't see: imagine what's happening in the electron-degenerate portion of a neutron star. The same process that creates the heavy stuff that gets tossed about from mergers is also going to create higher stuff that will decay before we ever see it.

(And I say that despite my own work and usual eagerness to tell people all about it!)

Life on Earth is mostly C, H, O, and N, but it makes use of many heavier elements to conduct complex chemical synthesis processes. Some are only used in trace amounts but are still necessary. Then there’s technology which could not have developed to this level without most of the periodic table. Low metallicity is likely to put a ceiling on what can evolve.

You’re not getting spacefaring aliens until you have the building blocks. Then it takes billions of years, and on top of that stable nurseries like Earth are probably rare.

So TL;DR my guess is that we are early and rare.

In a few billion years the galaxy might resemble Star Wars with aliens all over the place, albeit without FTL unless we are very wrong about core physics or there’s some huge aspect of reality we haven’t found yet.

The early star were huge and exploded extremely fast, like a few million years. It's likely they did this in rapid succession many times priming the universe with a lot of building blocks. The early universe was wildly energetic.