Great job so far, you're farther along than most real mechanic's would be at this point. It reminds me of an old 2000's Stratus I worked on that had all kind of electrical issues due to a shorted ignition cylinder lockout solenoid. That was a fun one to track down...
Looking at the wiring diagram, assuming this isn't a convertible or wagon, the following are powered by the CTSY fuse:
LF door lock sw
RF door lock sw
Luggage compartment lamp
Multifunction alarm module
Door unlock module
Given that you already ruled out the alarm module, and the drivers door switch, I would next try the passenger door switch. I know it's a pain. The dome light and luggage light are easy, just look to see if they're on. The horn works, I presume, so that's not a likely culprit. The only things left are the IC and door unlock module.
I couldn't actually find any reference to a "door unlock module" in the service info, but I did find reference to an "Automatic Door Lock Relay" that's supposed to be behind either the passenger kickpanel or behind the passenger side of the dash (Behind I/P on Right Shroud is what the manual says). This relay is activated by either the multifunction module OR either door lock switch. It's basically a two in one relay, where one side controls the lock function and one controls unlock. Try unplugging this relay and see what happens.
Also, when you find this relay, as another test, which I would do with the multifunction module DISCONNECTED (since you've ruled it out by swapping): with no door lock switch pressed check for voltage on either the black wire, pin F, or the light blue wire, pin A. If you have voltage on either of those with no switch pressed, there's a problem. The switches splice together before the relay, so because you've already tried disconnecting the drivers side switch it would point to either the passenger side or a short to power somewhere. If there's no voltage on either wire, you've got a short somewhere.
Just for reference, the multifunction module only controls the lock function, not unlock. So if the problem is on the unlock (black) wire, it can't be the module. The diagrams are very confusing, when I look at the power distribution diagram it's called a "Door Unlock Relay" but everywhere else in the service manual it's called an "Automatic Door Lock Relay". It serves both functions, however the lock side it the only one that the multifunction module has control over. Very weird.
Hope that helped a bit! A couple vodka's make it harder to translate diagnostics into words
*Edit again* If all that fails, you would have to start looking at the things controlled by the multifunction module. The only other outputs I can see on the module are the seatbelt retractors, as mentioned previously. Do all the seat belts work? None are locked up? Another easy check, although you may have already done this.