Randy: it sounds like you know your stuff. The relay will be a piece of cake for you. Only comment I have is: (for me anyway) it is difficult to tell when one of the bulbs is off unless the failure lamp lights turn on. If you are going to disconnect this circuitry, this is something to keep in mind.
Have you had the enlarger (head) for long? I have had my Omega F for many, many years and it has never given me trouble. Routine maintenance stuff: changing the styrofoam liners, cleaning, lubing certain parts. Had the dichroic filters changed (about 7 years ago). I understand they are indestructible.
Good luck with the project.