To be honest I never really paid much attention to the magazine disconnector mechanism in the '08 Vest Pocket. So I took out my pistol out, removed the grip panels and field stripped it to take a look.
Given that the magazine follower is catching on the disconnector as originally stated...
Q4: Is the magazine difficult to remove whether the pistol is cocked or not? I ask this because when the pistol is cocked, the disconnector appears to move into the magazine well. When it's not cocked, the disconnector remains in the forward position.
Q5: Is the magazine difficult to remove if there's a cartridge still in it or just when it's empty? If it is the follower, the magazine should come out easily if there's a cartridge still in it.
Observations with my pistol:
Both my genuine Colt and no-name aftermarket magazines when empty, exit just fine as the follower is no where near the disconnector.
What I think might be your issue:
If end of the magazine follower is sticking out far enough to where it's catching the disconnector, I think the magazine is at fault; perhaps it has a broken spring or someone took the magazine apart (can this even be done?) and put the follower spring in backwards, which can tend to make the follower want to push itself forward into the disconnector.
I don't think the disconnector can be in the frame upside down, but never say never.
Q5: Does the pistol otherwise chamber/eject and function as it should?