Chamfering every case to avoid over expanding sounds like an enormous waste of time to me. 45 Auto brass lasts a long, long time with regular expanding. You will lose them before you split them. You will lose some case length, however minute, every time you chamfer and 45 Auto cases don't grow, if anything they will get slightly shorter over time. The only time you need to deburr/chamfer a cartridge case is after you trim it, and 45 Auto cases should never need trimming.
I clean cases first then resize and deprime. I don't clean primer pockets on handgun brass and have never had any problems. If you clean with corn cob media after depriming you should run the cases through the resizing/depriming die again to make sure there is no media in the flash hole. More wasted time. I just clean my brass after firing in corn cob media and when I'm ready for a relaoding session I just load 'em up. It's pistol loads, not precision rifle loads, and sweating over all of the minutia won't make a bit of difference at 25 yards and less.