Regarding the section on your guide about infinity focus, isn't the purpose of the "past infinity" part of the focus ring to allow for the effect of different temperatures on the lens?The 16-35L II isn't parfocal. Thus focus must always change for different focal length settings. Temperature of the lens has little effect on where infinity must be set, in my experience. These lenses are very well designed to withstand thermal expansion. It still plays a roll, but not by any noticeable degree.
Also, the article is not saying anything about going past true infinity. It is only stating that to achieve infinity, you must not go by the marking and instead there is extra sharpness to be had by going past it a little based on lens variation from copy to copy. The test is to know where you should set infinity focus by knowing the offset for different focal lengths. Setting it to the marking still gives acceptable sharpness for the most part due to the hyperfocal distances. As you can see in the article, the added sharpness is very little but real.
The lens design also allows for the AF mechanism to hit infinity without hitting the stops when it must rock back and forth. It is important to give a bit of extra room for this to happen. I had a 70-200 lens that was too far out of spec, and at 70mm the infinity setting was too far past the marking, causing the AF mechanism to hit the stops and give up on finding true infinity, even though I could put it manually to true infinity.
It has nothing to do with zoom parfocal or not, if it did the primes wouldn't go past infinity yet they do.