Nero ordered the attack before he just happened to notice it was the Enterprise. I.e. he wasn’t even looking for the codes! Therefore we can be sure the codes were not important to Nero’s plans.
Not really. Nero might always have been planning on getting the codes, which would mean that he couldn't count on getting them from the starships that might or might not attack him; he would have some other target at the crosshairs for his ubiquitous kidnap-and-interrogate routine. He'd simply drop that target when Pike accidentally dropped on his lap, then.
I can't see Star Fleet, who would know about that possibility, just giving out access to their defences to every captain in the fleet
Some access would
have to be given, lest those defenses shoot down Starfleet's own starships.
Nero wouldn't be needing a string of numbers that paralyzes the entire Starfleet ("1-2-3-4-5... That's amazing! I've got the same combination on my luggage!"). He'd only need the sort of everyday access a Starfleet employee of relatively high rank possesses, so that he could infiltrate the system and start wreaking havoc from within. That's a realistic scenario for today already...
were the ships the Narada took out supposed to have been taken out all around the same time or spaced out over a day?
Starfleet learned of a "space storm" at 2200 hours; that storm apparently marked Spock Prime's arrival to the 23rd century, just like the previous one had marked Nero's arrival. Starfleet learned of the Klingon defeat at 2300 hours.
If Nero defeated the Klingons after capturing Spock, there's no "spacing out". But that allows Nero to defeat them with the help of red matter obtained from Spock, which makes a single devastating victory plausible. Also, that sort of helps explain why Nero fought the Klingons in the first place - perhaps Klingons controlled the space where Spock arrived (like they apparently had controlled the space where Nero arrived, being mere 75000 km away from the spot according to
Kelvin walla), so a confrontation was inevitable?
If Nero defeated the Klingons before capturing Spock, and Starfleet merely learned of the fact somewhat belatedly, there could be plenty of "spacing out". And that would allow Nero to defeat the Klingons without red matter. Again, Nero might have fought the Klingons in order to reach Spock; a series of duels instead of one massive battle would be a logical way for that to play out.
There's also always the possibility that Nero fought the Klingons for some reason related to the prison planet whose message Starfleet intercepted. Such as the original story concept where Nero escaped from said prison just moments before Spock's arrival - a concept totally erased from the aired version, and one that fails to explain why and how Nero got the
Narada back.
Timo Saloniemi