First research progress!
I've spent some time playing through the first part of the sith inquisitor story, where Zash appears in pretty much all the cutscenes. (I love the story and her inclusions so much!) Nina advised me to record them so I could play them back in slow-motion and take better screenshots, so that's exactly what I did. Here's what I've found out about the costume.
Apart from the screenshots, I made a 6 minute body scan video for myself after one cutscene where I could stay in a room with her: https://youtu.be/9oselPqHNms
I've carefully checked the video's and pictures against the 3D models that I found, and as far as I can tell the 3D models do have all the details that I see in the game from various angles. So that's very good news haha
3D model of Darth Zash, which I'm going for: https://swtor.jedipedia.net/en/npc/darth-zash-8
3D model of Lord Zash, simpler version before she becomes darth: https://swtor.jedipedia.net/en/npc/lord-zash
3D model of her later game appearance, where her hood is up: https://swtor.jedipedia.net/en/npc/darth-zash-10
If we assume that the basics of her outfit remain the same, which it looks like, that means that her Lord version 3D model gives a better view of the belt and the continuity of the seams on the front of the dress. Her old version shows that while you can't really see it, there is another red line under her hood when it's up.
One thing that I did find out from the game is that the dark red seams in the front of the skirt are actually standing outwards a bit. That's one of the challenges of this costume in general, is that everything on the 3D model is stacked on each other in 2D (ironically..). For example, there's no way to integrate the metal neck plate into the fabric, so it'll have to slightly lay on top. Same for the red chains with beads that hang from her belt. Anyone dealt with a similar situation? As long as I make everything as flat as possible, I hope it's not too much of an issue.
This will be a fun mother/daughter project because my mom is very good at sewing and I convinced her to help me with this challenge. She's almost as excited as I am. I've ordered some fabric (pleather) samples and can already tell there's a great difference between the colors you see online and what you get... The lighter red color almost seems like a coral on the 3D pictures, but in game it's redder. We'll start with a mock-up first either way so I'll have some time to go to fabric markets. Below are some screenshots with details. (Imgur album with more here: https://imgur.com/a/aAUJVSI)
Any and all advice/comments are welcome