I haven't heard the ESB 35mm mix in its entirety for quite a long time, but from listening to Darth Mallwalker's samples, the first laserdisc and the JSC sounded completely identical. As far as I could tell the only difference in actual content from the DC version was the snowspeeder crash sound; you are correct that the few seemingly different explosion and laser sounds in the battle are due to changes in mix levels and so forth--they are still in the DC but less loud.

I wonder exactly where the 1993 mix came from. SW came from the 70mm mix and had extra sounds put in on top of it, RotJ was reassembled from thirteen-track stems, while ESB is said to have come from an early generation four-track master. But what master would this have been? It is nearly identical to the 35mm version, but not entirely, and while its dynamic range probably reflects similarity to the 70mm, its content does not. It is possible the 70mm mix may not have had the snowspeeder crash sound either, but that's only speculation on my part. Furthermore the 70 seems to have had at least some of the dialogue differences of the SE, but not all of them, and possibly some that appear in no other version--but without a recording, it's impossible to know for sure. I find this rather confusing to think about!

I do recall hearing that TIE sound in the GOUT alternate language tracks. It also appears in the SE, but there the music is also different.