Credentials can be stolen. If no crew member knew the copilot by sight, perhaps the copilot was killed & his ID stolen.
Now, isn't that a thought... Indeed they can, and Facebook profiles, however our suspect's might have appeared before his posthumous notoriety, can be faked also.
Has all the makings of a grand conspiracy theory, except motive, aside from self-annihilation of course. It's the deliberate, calculated and even passionate annihilation of the rest of the crew and passengers that cause me to stumble. And it's hard to follow the evidence with this crime scene, eh?
And what about that Golden Gate picture... I could easily conjure up a message in that symbolism, and just as easily, I suspect, see the unconscious, apparently "innocent," and perhaps merely sad messaging in that subject. By all appearances, this was one very lonely individual.