Hi
@danzibar1 !
It looks like to me that probably 2-3 of the lower leaves could be removed from each plant, those leaves with the brown spots on them could be clipped off, this would help relieve the plant of older leaf growth that the plant no longer needs to survive with, and would speed up the plant in its recovery of this old leaf mass that is clearly in the last stages of leaf senescence.
In the picture above, the top 2 plants look a little bit thin/ smaller than the bottom 3, I'd probably just clip a single leaf or 2 at a time on those, too much all at once isn't good for them, especially if they are younger/slower growing individuals.
Those fan leaves that were left behind with the tips cut square, I'd probably locate those on each plant also, especially if they are looking discolored, yellow or brown on the ends, they means the plant is deciding to allow the leaf to fall off soon, if you notice that a leaf is ready to fall off soon by showing age or yellowing, etc, you can boost the plant into new growth by removing them for the plant, this way the plant can utilise that energy that the leaf is taking up, and heal from it and move on, with fresh growth on the tops of the plant and so on.
The bottom three plants can probably handle about 4 leaves removed at once, although if you remove just 1-2 every 24-48hrs it can be more helpful as the plant has an easier time reacting to a single leaf or 2 at a time , and you know just keep in mind that it's not good for constant removal of leaves and other manipulation to the plant to have occurring to it, so after a few days of removing leaves let it rest a week or so to let it recalibrate itself and prepare for new growth etc (<--this excludes light LST training of course).
They key to defoliation is to be certain that new growth is being shown afterwards and allowed to manifest itself (new growth allowed to mature to decent size etc) before more adjustments to the plant are made.
But yes most of the time that slowed growth is being seen, and brown and yellow leaves are nearby, typically these would be your culprit of stagnant growth, by removing these leaves for the plant, you can speed up growth weeks before the plant would have released them on its own, once those large fan leaves start to yellow and brown, they can be clipped, all they do is block photons from reaching past their area of coverage until they do fall off on their own or are cut off and cleared.
Hope we can help you get some new growth showing up soon enough my friend.