I would think you need a pretty small aperture to get large enough DoF at closish distances, much smaller than f5.6.
You can use ISO 100 (or whatever lowest is) but as you will be using a tripod the combination of small aperture and low ISO giving a slow shutter is fine.

Surely the shutter speed will be flash sync?![]()
God knows, I just use lights. Probably shouldn't have input to thread as my product photography revolves around my eBay listings where absolute perfection is not required!
I am going to rent two soft boxes.