The answer to all 4 of your questions is that all your plants seem to be suffering from a major phosphorous deficiency............most likely hungry for potassium too.
Nothing to do with "autumn" or defoliation or night temps..............they are hungry for P and K now that flowering is underway.
Remember too, what is showing in the leaves now, is a direct reflection of what was happening in the root zone 2-3 weeks ago, meaning these issues have been manifesting for some time already.
Keep giving what you already are.............old, damaged leaves will not recover, but the new growth should be ok.
At this stage, I would suggest a routine of plain water/fertilizer/plain water/fertilizer as a good feeding schedule until they pick up.