As for the trailers: You are right, I completely forgot the LD archives. I think that there are no more trailers at all, just some TV spots (like these 6 Aliens spots included on Abyss SE). Alien trailers T2 and T3 are both 1,85:1, everything else is in identical format as in AQ. WS T2 is also on AL disc 1.
I made some research about Giger’s Alien. It was Japan-ONLY DVD and there was also a VHS tape in Japan. Nothing else. I assume that the tape has the in-picture subtitles too and thus there is no way how to get a top quality recording without the subtitles. The copy I saw on the exhibition in Prague had no subtitles since that was a normal „celluloid“ movie from a projector. I recorded it with my cellphone (just for further reference). The e-bay DVD-R version is missing few secs on both the beginning and the end. The man who did the transcript from the LD (or VHS?) did not care much about the quality…
Meanwhile, I found two copies of the LD for sale on LDDb. One for 150 dollars, the other for 200. It is too much for me, I am sorry.
Until now, we were talking about Alien and Aliens. How about parts 3 and 4? Here is the answer.
There are two main Alien 3 Making of featurettes. Both approx 25 mins. The first one is available on disc AL3 and on a promo VHS tape in USA (also packed with A1 and A2 in a 3VHS box). The second one was included in the famous UK facehugger box on a separate VHS, also available as a promo tape in an extra big plastic case in UK. It is a part of the DVD-R Archive mentioned earlier in this thread.
The Making of Alien Resurrection included on disc AL4 probably comes from an EPK, I guess. Its length is just 4 minutes. But there is also a longer featurette made for HBO. It is much more interesting and Ron “Johner” Pearlman is a funny narrator. Released as much as three times in UK on separate VHS tapes (a “play daily tape” for stores; in A1-A3 4VHS box; and in A4 double-VHS set), never in USA. Also released in 3VCD set in China with Chinese subtitles in picture. Not long ago I found an US collector who recorded it in 1997 from HBO (original title: HBO First Look – Behind the Scenes of A.R.). I bought a DVD-R copy from him for 20 USD. 26 mins, NTSC, DVD made from the first generation VHS recording, the quality of the picture reflects this fact. Not poor, not best.
If anybody is interested…
And here is another video we can try to find: a 4:00 min reel “Aliens: Ride at the Speed of Fright” made for a 3D turbo ride back in 1996. It may be funny to watch it even if your seat does not move.