Re: Surviving Vulcan Elders.
There are two problems that I see with the "Temporal Prime Directive" argument.
1. The events of the new films take place before Starfleet had developed TNG-style rules about changing timelines.
Well, Spock was the very first character to warn us of the dangers of contaminating the timeline back in 1966 with Tomorrow is Yesterday
But we've seen multiple contacts with the Narada by 23rd century forces. The first contact in 2233 obviously altered the way Starfleet designs and constructs ships as we see the Constitution-class get a much later start in the divergent timeline. I would also think that some scans from both the Klingon and Starfleet encounters with the ship in 2258 would have survived as well.
"...the most elementary and valuable statement in science, the beginning of wisdom, is I do not know." - Lt. Commander Data, "Where Silence Has Lease"