1. Why in the music folder there are 2 files of the track for Andy's House (one called "house", the other called "fullhouse")? Does it have something to do with the Demo?

2a. The voice clips and SFX on the PS version are different from the other ports of the game, the later are reused in "Buzz Lightyear Of The Star Command". Why is that? Were they all recorded by Tim Allen, or did Patrick Warburton record the later clips? 2b. Just something to note, the PS version also has more lines when Buzz faces a boss.

3. Is it just me, or do the music files all have that "hiss"?

1. Not sure why there is a fullhouse.wav and a house.wav, as they are identical files (they both have the MD5 hash 50322BB8F70985841C59A86709BCC1CF). I can only presume that they accidentally put an extra copy in there for some random, unimportant reason.

2a. The voice clips in the PS version are actually still in the PC version, as the files are there, but for whatever reason, they aren't used in the game. I imagine this is likely due to something like copyright issues, which is also likely the same reason why the music for Andy's House is different for N64 vs all other versions. Keep in mind that this is just guess, and I believe that Tim Allen did do all of the recordings for buzz in the game, but I definitely can't say for sure. 2b. This is due to the same reason as part a). The files are all there, but for some reason they aren't used. While i'm guessing this is for copyright reasons, I will mention that this could for some reason be a random glitch during the porting process (although I find that outcome much less likely)

3. Yeah, the music files do all have that "hiss". It's just a result of imperfect recordings/mastering. Remember that these were likely recorded in 1999, although it could have been as early as 1998. The audio technology was not nearly the same back then as it is today, and it's likely the audio recording/mastering (and possibly converting/compressing) process at that time introduced that "hiss" somewhere along the way. It's not uncommon for nearly all older (and even lots of newer) .wav files to have a very faint hissing noise.