Those two droids were one of the hardest things to fix. I tried a few different ways around it, but eventually did it like this:
I made a new background plate, painting out the droid as best I could. I then used my subpixel tracking/translation programs to cover up the droids in the first part of the sequence (after cutting 3 seconds off the front of the scene), where the camera is relatively static.
Once the camera starts moving, I gave up on the subpixel stuff (it's not neccessary for fast moving scenes). On each frame I would paste my plate on top, aligning it against the rusting spaceship in the background. Then I would transform (a skew and a scale) the lower half of the plate so that it followed the perspective of the ground, then made a mask so the droid continued to be covered as it moved (because of parallax) relative to the spaceship. That took a bit of touching up because the edges of the mask sometimes made it look like a wobbling cloud.
Then it was a matter of copying and pasting to fill in the parts of the landspeeder behind the droid.
When it came to the audio I couldn't do a simple cut or crossfade because the sound of the little droid going "boing!" was still present. So I had to loop a small section of the preceeding scene. Just recently I went back to it and had to adjust the volume a little because of discrepancies in the volume (it sounded like the landspeeder got a bit louder, than quieter, as it disappeared into the background). There's a slight loop in the music but it sounds fairly natural.
David