The biggest problem would seem to be the cameos. Fox own the episodes, WB own the characters but I'm sure someone else entirely owns Lurch, Colonel Klink and all of the other characters who made cameos.
The simple solution would be to cut them out. My local station did that for commercial time. None of my tapes has them. I only know about them by what I've read.
Be careful for what you wish for, the idea of cutting them out would grate on completists' nerves who want the ENTIRE, original, unedited show. Don't believe me, look at all the complaints from Quantum Leap fans over how they replaced period songs in segments.
Heck I am a big fan of the old show the Odd Couple and was mighty peeved when I found out that the so called complete DVDs had songs edited out. It doesn't feel complete to me and to have to shell out good money for the DVDs apparently that is too much to ask for.