Thank you all for your input and experiences!
At this point most of the fixtures in question will get some love and others will become part donors. I may have found a source of new sockets and will see if they are as advertised when they arrive. Sadly the HPL conversion is out, sounded cool.
I have recently been approached about getting a lighting rig back in good operating shape and have discovered that all the fresnels (Altman 65's) had at some point been over-lamped with BTRs (1000w) lamps. Most work but some don't (from what I've heard), they all have significant surface finish...