There is one point that is not really covered in the rules, but it seems to me more of a technological question.

What exactly can one person do at a fixed position in a vehicle?

When you are riding a one seated bike, its fair to asume that all possible actions can be done while sitting in the saddle.

When you in a bigger vehicle, is it fair to assume that you can still operate all weapons from the pilots seat?

When the two man crew of a YT-1300 get into a fight are they running for the two guns and leave the pilot seat unmanned or can it be assumed that guns can be operated from the cockpit seats, just pushing buttons? Likewise in a two man fighter (Y-Wing)?

They (sort've) mention this in the entry for the Y-Wing. The implication is that a pilot at the main control console of a vessel can operate turrets that would normally be operated by another character, but the turrets switch to a fixed-forward position (instead of having a Fire Arc (All)).

...and unfortunately, Fire Arc (All) doesn't really mean anything yet.

...and unfortunately, Fire Arc (All) doesn't really mean anything yet.

It can mean a lot in a chase, to be fair.

You're right, though, that space combat "as is" is a little less-well-fleshed-out than would be useful (at least as far as supporting all the rules they have in place).