I agree on the Ds. I would trade Xhekaj or Strubble (I like Xhekaj better, but Strubble is the better skater) and bring up Mailloux to play RD, let him grow into a top-4 role at the NHL level. Habs can trade for a bottom-pair RD.
I had posted a year or two ago that I wanted PLD, but he was unreasonable when in-between contracts and he stopped in Montreal in the summer (I forget which summer). He would have been an excellent 2C for the Habs. I still feel like Newhook could be a solution if he had better wingers. Maybe Newhook-Demidov can develop chemistry, but he is a poor man's solution