All right, here goes. I made Darth Maul once, I'm good at analyzing costumes made of fifteen different types of textured black fabric.
Top layer: Overcoat/outer robe. Basically a hooded bathrobe with ties at the neck. Has VERY loose fit, especially the sleeves (armscye reaches his waist) and a fitted sleeve inside the huge loose one. Made out of something like ottoman or chenille, maybe a very heavy weight tussah silk, possibly wool? He gets rid of this when he puts the armor on and we don't see it again.
Flak vest: He's replaced the old tan one. Has both short sleeves and an extra flap coming from the shoulder. Shoulder armor is attached to the short sleeve, and the flap covers the top of the shoulder plate. Hoses from the gauntlet now are hidden under the shoulder plate, rather than going up the sleeve. I think you could get away with cotton drill for this, or the same linen as the inner robe with a bit of thin batting in the quilted areas. This is the only bit that would really need to be fitted to you, I think everything else could be made based on measurements.
Tunic/inner robe: Black, reaches his knees, has somewhat more fitted sleeves and a cowl neck. The front is split up to his waist, with the split hidden under the girth belt. And is that a single side seam pocket on his left I spy? It's hard to tell, but I think it might have sleeves made as one piece with the body, rather than the set-in sleeves you see on most modern garments. There might be a gusset under the arm to allow greater movement. The raw-edged piece at his right looks like a separate bit sewn on just to blow dramatically in the wind (drama is VERY important.) It reminds me a bit of an Egyptian galabia? I would use a midweight linen.
(Edit: Just found someone else's analysis with better images.
Dargas is probably right about the structure of the "skirt", but I think it's one piece with the top of the robe. You don't want to worry about your shirt coming untucked from your kama.)
Trousers: Plain black, loose-fitting but not baggy. Looks like the same linen as the tunic, again. Or, since they don't really show, you could just wear black pajama bottoms.
