Ok, summing all this up (more for my sake than anyone else's…)
Here's the surround audio content contained in this set:
From the 1970 DEVI/ATION portion: Atom Heart Mother album original 4.0 Quad mix 1970 (Audio Only)
From the 1971 REVERBER/ATION portion: Echoes original 4.0 Quad mix 1971 (Audio Only)
From the 1972 OBFUSC/ATION portion: Live At Pompeii (with 2016 5.1 Audio Remix) [Audio-Visual Material]
And of course (as others have already pointed out) there's this tidbit:
So essentially looks like I'm waiting until 2017 for these three volumes.