1. The temperature and humidity are going to dictate the flash time. You will have to figure that out. Apply to a certain area and time it. The coating rainbows so when it starting to dissipate that is when you want to get it off. Longer than that and it will be more difficult to remove.
2. Wash, dry, panel wipe and apply the coating.
3. Yes. You want to use a soap that contains no wax, ceramic or gloss enhancers.
The coating will give it a more rich appearance. It will darken it but make it look richer but not glossy. Here is a set of matte wheels to give you an idea.
The enrichen look will last a long time. Hard to say exactly how long as the climate is different for everyone.
The coating needs 24 hours to cure. After that you can drive it.
I prefer low nap pile microfiber towels. I use 300gsm edgless towel from a well known towel company. I find them to work better than a suede towel and super plush towel. Again personal preference.
The coating can get wet after 24 hours.