I analyze bearings for a living on a daily basis. You changed them just in time. Richard is correct, the discoloration on most of the races indicates localized overheating. This is probably from the oxidized (black) grease that was plain used up.

I'm not sure what to make of the reddish-colored grease, except that you're probably correct in assuming the seal failed, allowing water to creep in.

__________________
95 E320 Cabriolet, 169K