I installed the LUT-MLCs to each of the three affected circuits and the ghosting is gone. Simple solution. Could probably have saved the money on the PD-5NEs but the added neutral wire seemed like the more likely fix at the time. Hey, the preset dim button is worth the extra $60 each, right? Oh, well...
Had another ghosting problem with a PD-3PCL lamp module. My daughter has some non-dimming colored LED bulbs that I put on the PD-3PCL set for non-dimming mode. Three LED bulbs on the circuit and they ghosted. I wired a LUT-MLC to a two-prong plug and plugged it into the second outlet on the PD-3PCL. Once again, ghosting is gone.
Total system now is 24 wall switches, 2 lamp modules, 17 Picos, and the Smart Bridge for 44 of the 50 supported devices. Might add one more Pico. House is two-stories, 2400 sq ft. The outside lights are on timer switches and I didn't do bathrooms or closets. Those would have pushed me over the 50 device limit.