EDIT: After exhausting all options I tried cutting metal and drilling holes and finally found a technique that worked for me. I made a video of it for anyone that may get stuck is the same, but very rare, situation I got myself in:
I have babied my 2010 Honda Fit (base model) since I bought it new. Last year one of my rear door lock actuators stopped working and the dealer wanted to charge me $500 to replace the whole assembly. I decided to take the whole thing apart myself and actually find/fix what was wrong. After removing the door panels, window, part of the window channel, and the exterior handle I was able to get the whole mechanism out and upon complete teardown found that it was only a tiny 3$ motor that had burned out and would be easily replaced.

Long story short, while I waited for the replacement motor to ship, I decided to put the actuator and the door back together as the latch mechanism is part of the actuator and the door won't close and latch without it (didn't want to leave the door open for a week).

Today, I went to open the door and it won't open. Not from the outside, or inside. The manual unlock from the inside (and the cable it is attached to) seem to be functioning, but I can't for the life of me get the latch to release. I have the inside door panel off still and have removed as much trim as possible but without being able to open the door I can't remove the actuator assembly, remove the exterior handle (there is a bolt that is inaccessible), and I can't remove the window because I can't release the lower channel. Thus I have exhausted all measures I can think of for even accessing the latch assembly and forcing it open manually (not to mention that even if I was able to get access to it, I can't think of how I would actually get it to open).

I am desperate at this point and am hoping for any ideas anyone can come up with for how I can get the door open (or off completely). I am basically to the point where I am shopping for dremels so I can try and cut the visible portion of the striker (visible once the trim is pulled back) and then to try to somehow pry it open and see if I can get the door open that way. I also considered cutting the back plate to the striker from behind the column, but after tearing out the rear panel I see it is almost inaccessible.

P.S. I was all excited because I was going to make a how to tutorial to help anyone with the same problem. Now I am just sad because I'm worried I won't ever get my car door open again.

I have attached a photo of the culprit with part of the casing removed. This was prior to my reinstalling it while I waited for replacement. I have also included a picture of what my car looks like right now after many attempts to get the door open.

 

Any luck yet?

It would seem like the one cable may be unattached at the white section in the door? Possible to get a finger in there to operate that lever?

Did you put the burned out motor back in? I assume it goes in that hole with contacts at the bottom.

I have read through my shop manual and do not see any solutions.

Maybe have a look at the other door and see how the cables operate to confirm they are connected.

Good luck