There really isn't much for me to say in this post. Everything in Advanced Customization deals with pages hidden away in what's now known as the "Developer Area", aka /customize/advanced/. This hasn't changed at all, so not much will change in the relevant FAQs. The only thing that will is the de-emphasis, relegation or elimination of S1 information in them.
The existing S1 category will remain virtually untouched, aside from the following warning atop each FAQ:
→ Switch to S2 for the latest features and themes.
Minor wording changes throughout as necessary. Anything I've missed, or other thoughts?