Hi, Earl:
These are all interesting questions.
I do have one answer for you, though, yes, 284 still has conduit and several small lights in the center of the roof for the length of the interior of the car. I assume these are similar to what was installed in the San Juan cars. I believe these were trashed from all the remaining (D&S) vestibule coaches when they were rebuilt to steel.
I'll be waiting to see if there are other pictures from the last trains come to light. It might be harder to spot the others in distant shots because they are probably green like the rest of the consist. Have you seen the picture of the 280? I'll find it and scan it if anyone is interested.
Mike