⚠️SPOILERS⚠️
You're right, everything here is just speculation, but Alon does explicitly state that humans are in a constant cycle of reincarnation. They just shatter and return as one of the six races, over and over. Luke could easily have gone through multiple cycles already:
"No matter how many Humans claw their way back into reincarnation, they always end up shattering themselves back into the six under the vastness of that power."
"There have been many Humans through history. Each of them, a World-changer. Each of them, shattered and forgotten once again."
"You were careful with your power. Respected and avoided it, like you should. And yet even you had weakened and almost perished from it when pushed against the wall."
And I really want to know more about Dawn. It's a feminine name, which would actually make her the first female character in the story. The Observer seems to had a complicated history with her, based on his tone, she seems to have been a serious obstacle to him at some point:
"You... I know you. You are Dawn's brother, aren't you?"
"It makes sense why you would try to fuck with me. You were always on their side, right?"
I'd love to learn more about Luke's family in general. The main story feels locked into the loop of the Skies Ablaze day, so maybe a spinoff could give us a look at Sansun and his father Tharros, or at least have them appear in one of Luke's memories. Though honestly, part of me just wants to see them show up at Shelter someday. Imagine his dad walking in, looking around, and going "look at you, taming all these dogs and having them worship your cock, I'm so proud of you, son" ... okay I'll stop there.
On a more serious note, I'd love to see more of the other races too. The "Reincarnation" ending already hints at how interesting it could be to follow Luke outside of Shelter, him living in the Saurian kingdom (Also, Luke says that is a beautiful place) for a while sounds like it'd be a great story on its own.
Lastly, yes, Alon's route isn't replayable, which is why I went through the game's files, collected all the scripts and merged them into a single file (it's not clean, since the scripts are sorted alphabetically and not by chapter order). I just feed it to Claude to scan for specific lines I remember. It makes it a lot easier to revisit the parts I want to explore more deeply.