I don't think a plated surface for your tools is the best approach. The plate will likely crack when subjected to the pressure of using the tools.
Yes, you could plate the light fixtures without removing them. They must be a compatible base metal and must be free of dirt, grease etc. and highly polished prior to plating. Use Plug N' Plate™ See
http://www.caswellplating.com/plugnplate.htm
I can't say how durable a gold or silver plate would be under those conditions. Both are very thin and not renowned for long lasting properties in any conditions where wear might be encountered.