All right, got internet right now so I can do a little update. Thank you again everyone for chipping in! Made all the difference in the world!
I was able to open the rear door, then remove the panel and I messed around a long time to finally be able to put the mechanism back together but it’s not quite right. I think something has been damaged, or a some part broken that makes this all work together nicely.
I can now open the rear door with the handle but the handle is very stiff and not smooth like it used to be. It’s also easy for the mechanism to loosen itself from the handle if you pull too hard.
I’ve included some photos of the loosened mechanism so you might perhaps have some input as to what is missing/wrong.

That's from underneath

Here the handle is pulled out from the outside.

Here it's back in. There's such a distance between the metal part and plastic handle I'm thinking maybe a piece is missing?

And here that's as far the handle pulls out to unlock the door (the mechanism has been inserted back into the handle slot). The other handles pull out twice as more.
