RE the bearings, I wouldn't bother trying to revive them as a permanent fix.
As a temporary fix until new bearing can be installed, yes... but not
permanent.

RE WD-40, I've used it for years to prevent corrosion, as a cleaner, and to
dry out electricals... Never counted on it as a lubricant per se. It doesn't
seem to have anything corrosive in it if http://en.wikipedia.org/wiki/WD-40
is accurate.

WD-40's main ingredients, according to U.S. Material Safety Data Sheet
information, a

50%: Stoddard solvent (i.e., mineral spirits - primarily hexane,
somewhat similar to kerosene)
25%: Liquefied petroleum gas (presumably as a propellant; carbon dioxide
is now used instead to reduce WD-40's considerable flammability)
15+%: Mineral oil (light lubricating oil)
10-%: Inert ingredients

The German version of the mandatory EU safety sheet lists the following
safety-relevant ingredients:

60-80%: Heavy Naphtha (petroleum product), hydrogen treated
1-5%: Carbon dioxide