Good points! The line roller bearing is an often negelected component in spinning reels, but I'm not sure a ceramic is going to offer much in the way of performance over a good AR SS type bearing.
The cold would def. affect the the viscosity in bearings lubed with traditional petroleum lubricants, but the gain you would see from running your bearings with dry lube may be negated by the grease and the effects of the cold that is required to lubricate the gears in gear case.
I have tried neither of these, so I am just playing the devil's advocate, if you have had good results with this, I would like to know, may be something I could offer to my customers.