I couldn't imagine calling tech support only to have them say, "the photocell might be bad"
I would have wanted to crawl under a rock, especially if the homeowner was there with me. Usually the first thing we would look at, dont you think?
You would think they would at least have simply ordered an FX photocell. The time wasted searching the internet when simply ordering a new one from the original supply house would have taken 1 minute.
As for the answer to #8, there is nothing else to do when the ground is frozen and there is no snow falling