To the missing tracks, it would be possible for me to extract them it's a puzzle but possible. There is an amount of very short tracks which i even left out (some fanfare like stuff).
It really isn't easy to extract them from the .XMI files since each consists of (like i said) >60 tracks including repetive gunshots, shore noises and phone rings even in between the tracks which stand sometimes single in a XMI sometimes together with 1 up to 4 standalone tracks of music.
The linked mp3's will help me but i won't do that so soon, recently i'm satisfied i just liked to extract them to play the MIDI in DOSBox with a (various) DOS MIDI player (various: MegaMID, Ultrasound Playmidi, PX player which is a fine DOS player using the Miles Sound drivers).
Suggestions are welcome so please take a look in the linked zip and tell me if i picked the right tracks i'm not a dedicated DUNE player and can't tell which tune is played when, probably some are build of various tunes? it would be possible and smells like this by looking at the files.
(besides, thanks i found the DUNE1 midi's here - nonetheless would i like to know how to extract them, dunno if track 2 sounds proper with the gunshots at start (?) it reminds of what happens with the tracks of DUNE2 if you don't carefully split them you receive a mix of music and soundeffects)