Not much use speculating at this point, but you can draw parallels through other recent examples.
For instance, all those 3rd party add-ons for MS flight sims (both payware and freeware) are made with the respective SDK tools: a modeler will make a 3d model in a suitable editing software (separate to the SDK), then the SDK manuals tell people how to go about building a flight model, assigning it to the aforementioned 3d model, create some "hooks" for sounds to be played for each event and so on.
I don't own FSX but a friend does and he has quite a few add-ons, some of them are downright brilliant and it's how i learned CEM before CoD was even released (visiting him for a few beers and making 2-3 hour flights). In one of them i remember hearing a high-pitched whine when turning on the master switch, which was later overcome by the engine sounds after i would start them up...well, imagine my surprise when i learned it's the sound of the vacuum pump that drives the gyrostabilized instruments.
Just goes to show what is possible in general, but as far as CoD goes until we have some concrete information all we can say is plain theory-crafting
