Great update.
We loved Behemoth too when we rode it end of May. How are the trims nowadays ? When we rode it, all trims were of and we understood that there was somebody from B&M coming the week after to arrange the trims.
About the empty seats, we saw that too in in CW but we also saw that in the US parks we visited. I in fact can only remember that the ops of TTD bothered looking for single rides when there was an empty seat, but that was probably because of the trainweight which was needed to make the tophat at the right speed. Don't recall the KK ops doing the same though. Anyway, on all other coasters we did during our trip, the ops didn't really care that the train left 10 to 20 % empty.