Think I figured out what was going on in Enemies United mission 7, the subspace one where you meet the NHOL juggernaut (lol, lmao even). The Hurricane has three beam turrets facing the NHOL ships: two ****ty slash beams, plus a BFGreen on Turret09. In addition to a beam-free-all, there are a couple of fire-beam SEXPs for turret09 specifically. This means that the Hurricane's entire defensive ability is concentrated in this one turret, and sometimes it dies.

The reason we were noticing a problem with the MediaVPs specifically is that this turret is much larger on the hi-poly Orion than it is originally - the NHOL's initial volley of slash beams is much more likely to kill it and render the mission unwinnable.
[EDIT] Interestingly, when I first played and when Renegade Paladin did his playthrough, the mod had no MVPs dependency on Knossos, and played with retail assets unless you added it yourself. The dependency was added sometime in the past few months. IMO this is a "New Beginnings" situation where this campaign does not deserve MediaVPs

[EDIT2] Oh and! I also figured out what caused the "two music tracks at the same time, man" bug during the SOC Loop prompt. On the previous mission, you exited the debriefing by hitting ESC to replay the mission. Then you went back and continued the campaign from the mainhall - crucially, going right form the mainhall to the SOC loop accept/reject prompt. Apparently this particular code path
does not stop playing the mainhall music, but does start playing the briefing music for the prior mission (in this case, "success"), so you get both at once. I just confirmed this happens in a real actual campaign (FS2 after Feint Parry Riposte) as well.
Very hyped for Overload!!
[EDIT THE THIRD] Also Joe I submit for your consideration: The "WHAT?!?! Oh affirmative." message as a sound alert