I think that the current plan is to only use ceramic loaded grease for using on pad/carrier contact points, the silver/grey grease will be aluminium loaded grease, that is better than Copa Slip etc for use between alloy wheels and iron hubs, adding in a 3rd metal - ie copper, is not considered a good idea and any conducting greases should not be used near ABS sensors it has been said, nowadays.
Silicon grease is a good lubricant to use on calliper guide bolts or on guide pins that pass through a rubber damper, Red Rubber Brake grease gets used - goodness knows where on modern systems as it will not like high temperatures, but will not harm any rubber elements, whereas the Silicon grease will tolerate high temperatures as seen near callipers and discs.
Silicon grease is a good lubricant to use on calliper guide bolts or on guide pins that pass through a rubber damper, Red Rubber Brake grease gets used - goodness knows where on modern systems as it will not like high temperatures, but will not harm any rubber elements, whereas the Silicon grease will tolerate high temperatures as seen near callipers and discs.