On mistake #2, there is another way of viewing this that could actually make it a valid statement.
Often in General Relativity, physicists will choose what are known as natural units such that c = 1 and G = 1, c being the speed of light in vacuo and G being the gravitational constant. In natural units, both time and space have the same measure of distance. Even further, is the fact that when talking of trajectories along space-time, one no longer speaks separately of the time it took and the distance traversed. Instead, one only speaks of the proper time (for time-like trajectories with velocities less than the speed of light) or proper distance (for space-like trajectories moving faster than light) measured along the curve one takes through space-time. Both these measures, in natural units, have units of distance, which then one would convert by appropriate multiplications of c and G to get the normal physical units of time and space separately to which we are accustomed. There are special trajectories that have a proper time and proper distance measure of zero. These are the trajectories traversed by light itself.
Different trajectories would have different measures of proper time or proper distance, and would require different velocities at points along the trajectory in order to maintain the trajectory. The measurement of the proper time/distance along the trajectory is obtained by integrating the metric along the trajectory. In normal flat space-time, with normal physical units, the metric would look like this:
ds^2 = -c^2*dt^2 + dx^2 + dy^2 + dz^2
and in natural units, like this:
ds^2 = -dT^2 + dx^2 + dy^2 + dz^2
In a non-flat space-time, as occurs in the presence of a gravitating body, like, say, a black hole, the metric would be very different, and there would be multiplying functions in front of the square-differentials for each of the coordinates, like so:
ds^2 = -F(T, x, y, z) dT^2 + H(T, x, y, z) dx^2 + K(T, x, y, z) dy^2 + L(T, x, y, z) dz^2
or, even more generally
ds^2 = g_{u,v}*dx^{u}*dx^{v}
where g_{u,v} are the components of the metric and dx^{u} is a coordinate differential dT, dx, dy, or dz. Each of the metric components g_{u,v} can be functions of the coordinates, as prescribed by Einstein's equation,
R_{u,v} - 1/2*g_{u,v}*R = 8*pi*G*T_{u,v}
where R_{u,v} is the Ricci tensor and R the Ricci scalar, both of which define the local space-time curvature. G is the gravitational constant, and T_{u,v} is the stress-energy tensor that defines the distribution of mass-energy.
In general when trying to solve for trajectories through space-time, one finds what is called the geodesic path. This is the path that traverses the shortest distance of proper time/distance through the space time. According to General Relativity, the most natural and easiest path for an object to follow through space-time would be the geodesic. Any other path would require applying a real force (here's a shocker: gravity, in General Relativity, is NOT a force at all) to resist the object's tendency to follow a geodesic path from wherever it happens to be. For a flat space-time, the geodesic is to proceed in a constant direction at a constant velocity. In a gravity environment, the geodesic is to accelerate toward the gravitating body (I think you can guess where this is going!).
In an environment such as the Maw, the space-time would be severely warped and contorted, and the geodesic paths would very likely be ones that take you straight into one of the black holes. However, if you can sidle up close to a geodesic and just barely miss being on it, you can traverse the region along a near optimal path without falling into one of the black holes. The closer you are to this optimal path, the shorter your proper time/distance measure will be along the trajectory you follow, approaching the proper time/distance measure along the geodesic itself. Now, if you are measuring the proper time/distance along the trajectory you follow in natural units, then you could easily speak of the distance (i.e. parsecs) traveled along that trajectory, and you want to have a smaller number to be more impressive because it means you got the closest to the geodesic without being on it such to fall into a black hole.
Now, granted, Lucas likely was not thinking of all this; he likely didn't have much known of GR at all other than some dude named Einstein came up with it and E=mc^2. He may have had the whole curvature thing, too, but it's very unlikely he understood the gritty mathematical details. In fact, it is very likely Lucas simply heard the word "parsec" used at some point in the context of outer space and just assumed it was some measure of time because it has "sec" in it (sec = seconds). Even so, it turns out, by lucky accident, that the way he ends up talking about doing 12 parsecs for the Kessel run can, in fact, be valid, but only from a certain point of view.
ADDENDUM: Realized I forgot to make the distinction of proper time and proper distance more clear when working in normal physical units. In normal physical units, proper time and proper distance are related by
ds^2 = -c^2*dK^2
where dK is the proper time differential. In natural units, it would just look like
ds^2 = -dK^2
and time and space become interchangeable as having the same units. So, even Lucas' notation in the novelization of "standard time units" would still be valid under this scheme as long as time-like trajectories are followed through the space-time. For space-like trajectories, one can only validate the statement under natural units.
Of course, we all know what Lucas really meant and the fact he didn't have a clue what he was talking about. But, it still sounds cool, if you're willing to squint your eyes really hard through GR lenses.
