Your brass prep sounds like way overkill to me. First, I second the neck sizing with a Lee Collet die. Eliminates the lube completely.
If I need to FL size I remove the expander as MD says above or use a smaller caliber expander to decap, lube with the pad and lube the inside of the necks by just sticking the case mouth into the lubed pad then size and expand in separate operations. After that tumble to remove lube and load.
I use walnut media and can't imagine how a little walnut dust could be detrimental to the loads.
