The part about being able to play any part of FFVII on any disc, minus the FMVs, is something I remember testing ages ago on a PS1 copy of FF8 as well if I recall.
Essentially the entire game data is accessible on all the discs minus the FMVs. It's really cool to see how the biggest amount of space taken on these discs is the (for then) high quality FMV.
Same for MGS1. I remember seeing PC rips of the game that had all audio and FMV taken out and the game itself was barely 100~ something MB. I-e only around 1/10th of the actual data space of 2 CDs was the game, the rest was all FMV, audio or duplicated data.
Fucking crazy.