Is XI considered to be an alternate timeline within the original canon, or is it a separate canon?
Personally, I feel that XI establishes its own separate canon in that it is an alternate universe and not part of the original TOS/TNG/DS9/VOY universe (which begs the question, "why should I give a targ's booty about any of these characters since they're not the ones I know?"). Even though it is supposed to represent the original TOS universe up until 2233 when the Narada appears, I still believe that the Narada and NuOldSpock emerged from the wormhole in a wholly separate alternate universe. Therefore not a part of TOS canon.
If they’re the same canon, there are some contradictions that are difficult to resolve. For example:
The characters played by Zoe Saldana and Anton Yelchin bear little resemblance to the characters played by Nichelle Nichols and Walter Koenig. The differences are not something that can easily be explained by the Narada's impact on the timeline.
I agree.
Delta Vega is near the galactic perimeter in TOS and near Vulcan in XI.
Yep. That bugs the heck outta me as well. But the DV in XI is not supposed to be the same DV that we saw in WNMHGB. Or at least that's the writer's excuse for why its in the wrong place and has the wrong climate.
In TOS, starships are a rare commodity, so much so that an object could leave Klingon space headed for Earth with only one Federation starship in a position to intercept and that one starship isn’t even ready for launch. In XI, the Federation is able to gather a TNG-ish 40-vessel fleet at Vulcan in almost no time. At least five (Farragut, Walcott, Hood, Antares, and Enterprise) are on Earth and ready to go. Similarly, the Klingons are able to muster a 47-ship fleet to confront the Narada.
Actually, only 7 (8 counting the Abramsprise) ships went to NuVulcan. The rest of the fleet was engaged in the Laurentian system. As far as the Klingons, we really don't have a lot of information about the overall size of their fleet in the TOS universe. So that's hard to argue.
Pike appears to be much older in XI than in TOS, despite XI being set nine years before The Cage.
I've questioned this myself. If "The Menagerie" took place in 2266 (Kirk's second year of his first 5-year mission), and the events of "The Cage" took place 13 years prior (according to Spock), then that would put "The Cage" at 2253, 5 years before the Abramsprise was even launched in XI. If Kirk was 33 in 2266 (his age was established as 34 in "The Deadly Years" - Season 2-2267), and Pike was roughly his age in "The Cage" (Jeffrey Hunter was actually 41, I think) then Pike would be 36 in 2258. He looks more like 50-ish in XI. So he would have had to be born 14 or 15 years earlier, an since he was already born prior to the Narada's appearance, it can't be blamed for this inconsistency. So yeah, that's a little hard to swallow.
The Kelvin has escape pods with which the entire crew is able to evacuate the ship. Federation ships in TOS apparently have no such capacity.
Actually, the Kelvin used shuttles for evacuation. I don't think we've ever seen escape pods on a starship prior to TNG except for the NX-01 in "In A Mirror, Darkly". But the sheer number of shuttles on the Kelvin stretched the limits of suspension of disbelief. Especially considering the scene when Robau's shuttle exits the bay. The size of the shuttle compared to the size of the bay would seem to indicate that the entire secondaray hull was a giant shuttlebay if we believe that the ship could hold 30+ shuttles. And later, when the other shuttles are evacuating, they are leaving the ship in a single file line through a "corridor" similar to those used to launch Vipers on BSG. Interesting, yet wierd.
In TOS, Chekov is 22 years old at the time of Who Mourns for Adonis. In XI, he is 17. But XI is set nine years before WMFA. (Maybe it’s possible that the Narada's intervention caused him to be born several years earlier than in the original timeline, but that seems like a stretch.)
Yeah. That was in season 2. So if Kirk was 34 and Chekov was 22 in season 2, that means that Chekov was about 12 years younger than Kirk in the TOS universe. In the Abramsverse, Chekov is only about 8 years younger than Kirk. I find it a bit of a stretch that the Narada's incursion into the timeline somehow caused Chekov to be born 4 years earlier.
In XI, Scotty has a tribble at his post on Delta Vega. In TOS, removing a tribble from its predator-filled natural environment is a disaster.
True. And the Enterprise crew in TOS had never heard of tribbles before. And if he had been aware of them earlier, it would seem logical that he would have warned Kirk not to let the bloody things on the ship.
Can all these differences be treksplained by the Narada’s intervention, or are they not required to be?
Most can't be explained away simply by the appearance of the Narada. But, as far as I'm concerned, they really don't need to be since the Abramsverse is a separate alternate universe and in no way connected to the original TOS universe. There are too many differences prior to the Narada's appearance for it to be the same. That's the way I feel about it anyway. YMMV.