Killer grow BTF... Very nice.

The flowers look great but I wonder if any of the early yellowing was due to heat stress? Did you ever have any luck getting the temp's closer to 25º C?
I know you already have a lot going on in your closet but maybe you could get another inline fan and use your existing one for room ventilation and another for pulling the heat off of your lighting? You could take the output from each and use a Y adaptor to exit the airflow together out of your existing ventilation outlet. This would pull the heat off of the light with more efficiency and your charcoal ventilation will be more effective as well.

One thing that helped me when I did a closet grow a few years ago is I used 6" (16.5cm) PVC for the ductwork and it really works great. There is much less drag than flexible duct work even when you use PVC elbows to re-direct the flow. PVC fits tightly together without cement and it is easy to cut to custom lengths.

I look forward to seeing your girls finish up... then comes the Trainwreck!