The truth is : none of them.
No...that's not true. Not if you want full functionality.
It's true that the computer will run just fine without the ATK package, and some function keys even work. But not all of them. Nor will the backlights. I think most owners would prefer to retain all the basic functionality in lieu of absolute minimal processes. Clean becomes TOO clean when things don't work as expected. (Though I don't care about the ROG button, either! ;o))
I've tested lots of clean installs on this model, and though I see your objective, I have to disagree with you. You do get a lot of "partial" functionality even before certain basic drivers are installed, but this tends to eventually catch up with you. Without the Realtek HD audio driver, for example, you lose most options to tweak the audio since you obviously don't have the Realtek Manager, and many add-on programs (like THX TruStudio) won't recognize the audio device without it. Similarly, the basic Windows TP driver works, but offers no gesture functions, which are kind of the whole point of these multi-touch touchpads.
In addition, different users have very different needs....WLAN and BT but no LAN may be ideal for you, but others may need different network options. I disable webcams and BT in laptops that have them....but that's certainly not ideal for everybody.
These are very powerful computers. They have more than enough capacity to run all their basic hardware drivers without missing a beat. (There's also no advantage I've found to bypassing the manufacturers' installers.....but there's the obvious disadvantage that you have a much greater chance of improperly-installed drivers.)
If you want a minimalist setup, that's fine. But I don't think it's an advisable approach for most users.