Well... that one I can (sort of) answer, because making Morticia rare isn't in the original game, it's a story thread introduced in the Renpy version.
In the Unity game, we've only had the one interaction with Collector Morty (
offering the Portal gun after saving Morticia form the Creepy Morty: Day 21: Chapter 4: Maid Rescue). However, he shows up a few extra times in the Renpy Remake, specifically in a later scene:
Day 37: Chapter 9: Morty's Choice, where he monologues one of the reasons he is after her.
As I've already written the main conclusion (and answering this question isn't part of that (and Ferdafs version doesn't have this plot thread, so he'll never answer it (although, now that I've typed all this up, there might be some wiggle room to slip it in (that's what she said). I'll consider it.)), I feel okay talking about it here.
But, fair warning, you most likely aren't going to like the answer(s).