Also, regarding the missing snowspeeder crash sound in the 1993 audio mix of The Empire Strikes Back — I think I found it. Here’s a clip where it can be heard:
https://drive.google.com/file/d/1sGFi3gcT7Dc7R7dGsEhI6XrwxUIIVT3e
Took me a few listens to hear the difference. It’s not quite the crash itself that’s missing but rather the whirring sound the snowspeeder makes as it’s about to crash.