YMMV=Your Mileage May Vary. Meaning you might have different opinions on this, or you might choose some other method.
The cleaning part makes sense because you don't want to incorporate dirt into your polishing compound or your polishing clothes. The spray worked really well, for me, to remove the remaining surface corrosion. Then polishing compound didn't have all that grit in it which made final polishing even easier and with less chance of additional scratches.
This is just what I tried and the results were really good on badly corroded wheels as long as there's no clear coat on them which I'm pretty sure yours does not have. I tried the spray on wheels with clear coat and it did absolutely nothing to take that off but works well on bare aluminum. Again, you'll have to determine what you ultimately want to do.
I, personally, would stay away from wire brushes of any kind, brass or steel.
Good luck with your project.
ETA: If your rims are heavily pitted the steel wool might "catch and shred" on the rough surface. If that happens just skip that and go directly to the Mother's and any other polishing creams to achieve the result you want. And I wouldn't use any steel wool courser than 0000# since it might cause scratches. (I'm no expert on the use of steel wool.)