I can clarify, but these are only ... "clues" ... ; it COULD be due to the way(s) I tend to play my savegames; how I progress, when I "stall" the Main Plot to make money and upgrade, etc.
I wish there were definitive facts about precisely WHAT stimulates the individual additional cinematics to occur. But it's obvious that at least some of the time, WHICH CD is in the drive seems to matter (example the Ralph McCould situation, CD 2).
I can play P2 "the usual way"; swapping CDs.
( Actually there is a difficulty, my CD #3 is a little glitched... usually the Kappa Labs video stutters badly and sometimes crashes the game... sometimes ejecting / re-seating the CD helps. Doing a NO-CD hack seems to always fix this issue; I guess the Kappa Labs video ALWAYS copies onto HD Ok when done thru the DOS XCOPY command. )
Anyway... when swapping CDs there are "*TENDANCIES*" for the additional cinematic missions; their order, when they occur, etc.
As I mentioned, a long time ago (2+ years ago?), I figured out that I could copy the 3 CDs to HD, change all CD references in MOVIES.IFF to "1", and set CD.DAT to "1". The "*TENDANCIES*" were quite different. Note that entire *series* of savegames were developed this way, starting from a new game.
If I much later re-installed P2, re-copied that savegame archive (savegames from a hacked configuration, set to CD "1") back to HD, BUT did NOT bother doing a No-CD hack (I.E. swap CDs), then when loading those savegames, I noticed some peculiar behavior. Playing FROM any of those slots (especially the last 1/2 to last 2/3), the additional cinematics showed DIFFERENT tendancies. In fact, the game seemed to be trying to "rush" and "catch up"; additional cinematics were occuring as soon as I took off, as soon as I landed, WHEN playing FROM those savegames (developed UNDER the No-Cd hack) and playing IN a normal swap-CD configuration.
This seems to imply that the game is in fact "sensitive" to actually swapping CDs. It SEEMS to "know" if you quit the game, and, say, changed from CD1 to CD2 or CD3, and then re-started the game.
Now, if that's true, then what happens when "the CDs are never changed"; I.E. a No-CD hack that makes all movies come from "one big CD" (actually the hard drive)?
From my experience, this DOES have an effect. For example, in a normal swap-CD configuration, the Louissa Phillips situation seems to ALWAYS occur much earlier then in any NO-CD configuration, and also the opportunity to make 10k credits occurs if she "survives your next 3 missions". In a No-CD setup, Louissa Phillips tends to occur MUCH later, and in fact she never seems to show up again and you never get a chance for that 10k credits.
In a No-CD setup, Ralph McCloud seems to occur much later than it should (a couple of times it didn't occur for me until AFTER the Main Plot. And I HAD been flying around a LOT, clocking hours, miles, and landings trying to MAKE it happen). BUT, then, as I indicated, if you CHANGE to a swap-CD setup, Ralph McCLoud somehow gets "stimulated" to occur.
So... basically, (shrug). I can't SWEAR that the info I presented is true, it's just a strong "feeling". Digging into the game mechanics / EXE might be informative.
(EDIT) Also, I DID experience problems when the CD refs in MOVIES.IFF and CD.DAT did not match, and when all CD refs in MOVIES.IFF were set to "CD 0". I don't know, this MIGHT have been an anomaly, or maybe it is due to OTHER combined factors.