Question hairs are turning orange I know at least ...

from what i see you have a other 4 to 5 more week so the flush should be 2 week prior harvest from this pics its all white not orange yet only tips are and harvest is mostly around 80% orange + beginning to turn amber(all tricome)yellow leaf is normal and they will loose a lot but you can help whit adding nitrogen + brew compost tea+ seaweed extract all organic to better the taste and smell when dry/cure properly

From my experience buds are not ready till a week or 2 after breeders flowering time. So start flush around this time. If u can't get a magnifyer to check trichomes go by this. You have 3 to 4 weeks left to me. Since you are growing in a soil less medium u only have to flush 5 days the most. And the yellowing is normal she will start to shed leaves this close to harvest.

It looks like you have quite a bit to go still, 3 weeks i say. The pistils are still shooting straight up and the calyx's haven't swollen yet. Once the pistils start to curl I suggest to start looking at the trichomes on the calyx's and not the fan leaves, as the fan leaves will darken faster. Sometimes the plant will start to cannibalize its' own leaves mid flower if they aren't efficient, meaning not receiving enough light or if the feed is low (not bad that it is low). It looks like possible N deficiency, the pale leaves on the bottom, which is good at this point of flowering as they use very little N. I wouldn't change much and not start to flush for another week at least.

By the fact that your plants are in flower week 3 I would wait at least 2 weeks before starting to flush as now they need a lot of nutrition for building up and fattening buds. I never had any plant that was done before at least 6 weeks of flowering. I normally start to flush when at most clear trichomes have turned into milky ones. So after flushing some should have turned to amber ones. But that also depends on what you want. More amber means more stoned, more cloudy means more high. Surely the effect also depends on the strain and the unique terpene profile. Every strain and seed is individual. The trichomes will tell you best when its time to flush.