One of the three plants in the 5 gallon DWC is alm...

Hi bro ! Why don't you close that question by picking that answer ? 😘

M8 i think you been precipitated in harverest your plant in my real opinion it was not ready yet on the full potentiality. Using a common tank you getting this troubles. It is not bad change to ph water and then half of dosage on nutrients till flush again. Be patient m8 Happy growings

I suspect the 'red hairs' just a phenotype expression. Get a good look at the trichomes, I would be they are the same across the board. A few more weeks is what I would do if these were mine.

Unless your speaking of another plant that’s not pictured all of those plants have atleast 4 more weeks

Well now you know why they recommend not using a common tub. I assume that it is not possible to separate them, else you would not be asking here. Whatever you do it's going to have consequences, either you don't flush and the first plant will taste really harsh or you flush and the other plants will suffer in this stage. It's really a coin toss; personally I would do a small flush of say 4 days and harvest, then resume feeding for the others and make sure to cure really good the first batch.