All three shows are more ensemble now, so everyone should be considered, imo.
I'd like at least one of the women included. With Fire, if we go for Matt and Kelly we should also include Sylvie, because they're each in charge of their rig. That further complicates things though, because so is Herrmann now
For PD, I would say Jay for sure. Probably Kim and then Atwater or Ruzek. With the stuff that came out when Sophia left, I'm not sure how people would respond to Hank being included.
Med - Will is considered a lead, but he also tends to be a polarising character (people love him or hate him), and med is the most ensemble of them all, so they all fit. So it might be worth just seeing who works best for you all.