AW new game mechanic

I've noticed a few new things going on in the game. I know why way around a truck xml fairly well but I don't really know a huge amount about how games work and the terminology, so I hope this all makes sense! Here's the things I've noticed and the questions that have arisen from it:

The USA trailers have the InstallSocket "KamazTrailerCart", which is the same as their Russian counterparts. The Russian trailers don't appear in the addon selection list but can be attached when spawned separately (and vice-versa; USA trailers can attach to Russian trucks but don't appear in the addon selection list).

Could this be manipulated? I'd like to do something similar for the semi-trailers, and I'm also planning on changing the InstallSocket for the USA medium log trailer but doing so will probably make it unable to attach to the Russian trucks.
All the mods I've checked only have the Russian trailers in the addon selection list, is it possible to dictate which trailers appear or even have both?

Selection Screen Partitions
On previous versions of the game, you could place the Ridge and Valley truck xmls in the same folder as the base game's truck xmls and this would remove the DLC partitions that separate the trucks in the vehicle selection screen. This doesn't happen anymore, the partitions persist regardless of where you place the xml files.

There isn't a '_dlc' folder in anymore. My guess is that maybe the game was using this folder as the reference in previous versions, but now it is using the separate _dlc zips? (Although this doesn't explain the existence of the _dlc zips in the first place)
Is it possible to remove these partitions, add new partitions or dictate the order they appear in the selection screen? Ideally I'd separate the base game trucks from my installed mods, merge the Ridge and Valley vehicles with the base game vehicles, and move the AW section to the bottom. I remember browsing a large text file in the STMod directory that mentions these partitions (and a whole host of other features) but I don't have a clue how to do it or even if the text file is just a legacy from ST? I don't have STMod installed atm (waiting for the update) so I can't check the file again.

Driver Change
If you only have Russian trucks spawned in the Proving Ground, you will have the Russian driver. If you then spawn a USA truck, the driver will change to the USA driver, regardless of which truck you're driving. All of my installed mods have the Russian driver as standard, which then switches to the USA driver when I spawn a USA truck.

I much prefer the USA driver so I've replaced the Russian driver mesh with the USA driver mesh, effectively forcing the USA driver permanently. But could you force a particular driver via the coding, or even 'fix' it so that you have the Russian driver when you switch to Russian vehicles and the USA driver when you switch to USA vehicles?

Not Suitable For Offroading
This appears above the addon selection list at the garage and on the vehicle selection screen for the three 6x4s of AW.

I've removed it by deleting the line from strings/game, although the '!' remains on the billboard (I think it's actually a part of the billboard itself and not added afterwards like the text). An idea I've had though is maybe you could add this to all RWD vehicles like the ZiL, ZAZ etc (and any RWD mods you might have installed) so you could tell at a glance which vehicles are RWD?

I'm guessing it's all controlled by the lua scripts but this is the part of the game I've yet to delve into, so I don't really know what I'm talking about! I was expecting to find some sort of master list in the lua that dictated when/how/why these new features appear. I searched a few keywords like USA, Kamaz, Ford etc to try and start teaching myself but I've found nothing. Anyone know of a good thread or page where I can pick up some decent basic info on how ST/MR's lua files function?

Well I guess this wasn't half as interesting as I thought it was lol

Today I tried adding the US addons to a few mods and the standard trucks but none of them are working. I even tried changing the InstallSockets with no success, seems like they are locked to the US trucks? Wheels transfer over fine though, very odd!