King Daniel wrote:
I'm half-expecting John Harrison to be revealed as Khan or a Starfleet-bred Augment, either found and thawed or created shortly after the initial timeline disruption 26 years before.
I want to know if Starfleet or the Enterprise saved Nibiru from the erupting supervolcano in the prime universe! I'll be scouring future TOS novels for an offhand mention somewhere.
I really don't want him to be Khan, but I like your second idea. The problem with him being Khan, as I see it, is that from all appearances Harrison is in fact a rogue SF officer. For him to be Khan, SF would've had to have found the Botany Bay a couple of years prior to the events of the first movie and then somehow convince Khan to join. It's possible, but I like the idea of him being a totally new character.
And like you, I'll probably be looking at future TOS novels for references to Nibiru as well.