Working in the Automation industry, I have spent a lot of time with hydraulics. The oil used in hydraulics can and does break down teflon tape over time. (I have retrofitted many 1000 ton or larger presses that have the pickup screen clogged to some extent with the tape residue...but that is not normal)
(Note, I am in the boat that thinks teflon tape and the Limited contact time with PBW.... will not result in any issues. If left in constant contact with PBW for MONTHS...yes. But not for the few hours of soaking)
The "best practice" in the industry, however, is not to abolish teflon tape all together. Rather it is just to make sure it is not preset on the first two threads. Essentially, if you dont have it exposed and "flopping around" it stays in place perfectly. The tape when lodged between the threads, does not degrade.
With that in mind, I would use teflon tape wherever I needed a good water tight seal, and just make sure to apply it so that it is positioned in the threads and not exposed.
(Assuming you are worried PBW will effect the tape )
In the kettle, I see white tape exposed... I would re-wrap the fitting so that it is not exposed to the kettle, and I would keep the first two threads clear of tape as well.... since it is being inserted into the coupling.
I can say that I have tired my pickup tube in my kettle with and without tape. I had issues getting an air tight seal with my tube without the tape... but even without tape, enough gunk built up in the threads and fittings, after about 5 or 10 batches, that it became air tight.
I have since re-built the pickup tube and always use tape.
Good luck!