Option c) will definitely involve wet sanding the car...there is no other way to remove the orange peel. This is due to the fact that when you polish the car with a regular pad and polish, it will conform to the peaks and hollows of the orange peel, and will remove pretty much equal amounts from the peak and hollow, thus leaving the same finish. What needs to be done, is to shave off the peaks, to level the paint and then polish the finish.

Since you are considering doing a fair amount of work, in removing deep swirls from the paint, it might be worth considering a certain amount of wet sanding. BMW paint is very hard as you know, so compounding can be quite a bit of work in itself. CarPro do Velvet and Denim pads, that are the equivalent to 2500 grit and 3000 grit wet and dry. Therefore it might be worth starting with that, and finishing down as you would be normally. Doing such an intense job, and getting a good finish, but leaving the orange peel as bad as it is currently, might be a bit frustrating. Im not saying to go all out and chase every bit of orange peel, but even if you improve on it 50% would be vast improvement....although, will you be left frustrated, you didnt go the whole hog! :P I suppose thats what is the difficult decision.

Did you struggle with holograms on BMW paint? The rotary should be no problem for finishing down BMW paint...Honda paint for example would be. A very soft pad and a good finishing polishing should leave nothing. Everyone has their own preferences of pad and polish combo when working, but for cutting, I always found Scholl S3 Gold on their Blue pad, great, leaving very little in terms of finishing afterwards. Chemical Guys V38 is a polish that can be worked for quite some time, and that on their Black Hex pads, was usually ideal...even though the Black isnt their softest pad.