You don't have to mess with the lock assembly......when you operate the handle from the outside, does the linkage move the latch on the lock assembly? If it doesn't, and the linkage is attached to the door handle, you need a handle.....
One thing that might help you is this: there is a rear window guide in the way....remove the bolt at the bottom of the guide bracket(window must be up), and then push the guide upward about an inch, and it should disengage and can be removed.....
Also there is a plastic plug in the door(about the size of a quarter), in the
upper left corner....pop it out, and I think one of the 10mm bolt/nuts is behind it.....the other one is at the opposite end of the handle...