Luminous intensity is even more important than color temperature, which the AMA guidance acknowledges, but unfortunately did not discuss. Frankly, the references cited in the AMA list were a bit disappointing in how high the ratio of mainstream media articles was compared to actual research papers. It’s not that the AMA guidance is wrong. It’s just really limited in its utility due to the limited depth and breadth of research it relied on.

One study that does look in a very cursory manner at intensity vs. color temperature is here:
https://www.sciencedirect.com/science/article/pii/S0003687016301582?via%3Dihub

Basically, low intensity (0.1 lux) 2700K light was their control, and all higher intensity (200 lux) test cases even down to 1600K exhibited more melatonin suppression. I don’t have a lower limit of significant effect handy, but that factor has been more studied in isolation, and a decent figure probably determined. The impression I get is it is somewhere below 10 lux for incandescents, which actually is quite a bit of light, but I don’t know how far below.

Also, I think it’s well worth discriminating between high traffic highway lights not in close proximity to residences versus and those that are in proximity and illuminate low traffic areas, because we have to keep in mind the reason those lights are there, which is safety. More neutral lighting, compared to warm tones, provides better alertness and acuity, and depending on the colors of objects illuminated, can provide significantly better object discrimination and perception. So I suggest that using neutral white lighting in areas where it has a low potential to effect circadian rhythms is prudent.

I don’t see much reason to use violet-pumped LED’s outdoors. It’s just not an application where I see a need to chase the best CRI possible, so the conclusions you reference of Dr. Longcore seem reasonably easy to abide by. From what I’m seeing, his research seems mostly relevant to critically sensitive areas, like sea turtle hatching grounds, where users are being encouraged to use amber or red lights.