The rear door of my '92 2WD softtop tracker has rattled for years, and it's getting worse and beyond annoying.  I attempted adjustments as pictured, with no improvement.  What's the fix before I start throwing parts at it?

Well, you found all the adjustments; if you adjusted them correctly I don't know! 

Is the rattle coming from a loose-fitting door? Is it latching completely, or is it stopping at the first catch?Mine rattles when it's not latched soundly.

Have you popped the door panel off to see if anything is rattling inside the door?

On mine the hinges were loose and it "clacked" when the suspension topped out. Mine's a hard top though, and the door is a lot bigger. I tried to shim the hinges, but never got completely rid of the noise. Now I just turn up the volume. 

I had a rear Tracker door that was driving me crazy offroad.  I had adjusted everything to no avail.  I even started pop riveting the inside supports to the outside skin.  Still lots of noise.  I finally found my problem. It was the spare tire.  Stock there are two rubber supports for the tire at the top of the door.  This was not enough.  I simply added a third rubber support at the bottom of the tire.  No more noise.  It even is working with my current 31" tire. Hope this helps you.

I had a rear Tracker door that was driving me crazy offroad.  I had adjusted everything to no avail.  I even started pop riveting the inside supports to the outside skin.  Still lots of noise.  I finally found my problem. It was the spare tire.  Stock there are two rubber supports for the tire at the top of the door.  This was not enough.  I simply added a third rubber support at the bottom of the tire.  No more noise.  It even is working with my current 31" tire. Hope this helps you.

That's where the noise comes from on mine too.

.....the old bias ply swampers cover it up pretty well.

I had a noise coming from my back door like nails on a chalk  board at every bump. I took the cover off and it was the spare tire mount welds. Desparate for an immediate fix I masked off anything important and pumped a whole can of expanding foam into the door to help support all the framing members. $10 fix worked great.