Griot's Garage 6" is the way to go for a non-professional. Even though some professionals do use them, it's all that's needed to maintain your personal vehicles.
I would certainly take the opportunity while it's removed to clean and rinse out well. If you have trouble keeping it on, you could try a small bit of glue to reattach after the foam has been cleaned...
Every time you touch paint you are introducing marring/scratches at a microscopic level, it's about using the proper tools and technique to minimize the chances of you seeing them.
By using this method, which I have, I will still foam the car and then use the technique mentioned above for the remainder of wash. Thus eliminating the use of the soap bucket.
You could certainly check to see if Laboratoire Hygienex Inc. has a forum, I'm certain your questions could be better answered there.....if they have one?
I agree with it being body filler cracking. You can actually see where they tried to form that curve on the inside of the bezel with body filler and didn't get it quite smooth. Look above the crack...