Some notes:
1M3.
You’re right that some stuff was probably cut here, but it was probably awkward extra battle footage (we have some other not so stellar looking shots in the early assembly in the Making of Star Wars book). Worth noting that you can also see a jump cut in the shot you’re describing in the final cut so maybe things did get shuffled around last minute.
1M4.
Like I say below, scoring happened so late in production, and the trim you’re describing so exact, that there very well could have been a trim of what you’re describing.
2M3.
I didn’t even know there was speculation something had been cut. The little woodwind flourishes match up pretty well with Artoo turning his head and the Jawas ducking, and that sync stays even with where the cue starts up in the final film (aside from the bit tracked from the very beginning). Maybe Mattesino was thinking that the cue was meant to start in the same place that it does in the final cut?
3M3 Rev.
We can see from some photography that during scoring that many (maybe most) of the effects were being cut in, as there’s a photograph in the Making of Star Wars of him scoring 10M3-11M1 with visual effects in place. That to say that yes, I think the landspeeder scene probably had full effects. I think the shot we see in the final film is a much longer version of the shot that was in there during this stage of development, replacing that conversation from the rear-projection photography.
7M1.
I think you’re bang on. That footage was most likely shot for the Battle of Yavin and just happened to represent the hustling inside the station very well.
10M3-11M1.
It would make sense Gold Leader’s sign on had been cut at one point right? He’s kind of an incidental pilot. I think it also makes sense that after a screening or two they’d realize they had to establish him better before the battle itself. Notice also the attempts in the theatrical mixes to (unsuccessfully) mute Biggs’ name from some of Luke’s dialogue. I think the question of how to make the battle intelligible to the wider audience was something they mulled over quite a bit.