Requirements: Black series 3.75" Rey (Base figure),
Last Jedi 3.75" Rey: Jedi Training (Used for head, blaster, blaster holster, and lightsaber),
thin grey fabric (Pants; I used an old bed sheet),
textured black fabric (Tunic and midsection under-wrap; I used an old tote bag),
elastic band (Over-layered fabric; I took this from the same bed sheet I tore up for the pants),
leather cording (Belt) ,
dark grey fabric dye (Used on the elastic band to match the grey coloring on her film outfit),
brown, black, and 'flesh' acrylic paint (Painting the boots, molded tunic on the torso, and hands/ stray skin marks
respectively),
exacto knife (Cutting the leather cording and painter's tape),
basic sewing skill (threading a needle, making simple stitches, tying a square knot),
shrink wrap (Used for boots. Make sure the diameter of eh shrink wrap is wide enough to slip on over her feet, but not
too wide that it will remain loose after shrinking),
heat gun/ heat source (WARNING: Ask parents for help here; mismanaging heat sources can lead to ruining your figure or
burning yourself!)
painter's tape (Criss-crossed lacing pattern on the back of her boots. I admit, this doesn't show as well as I'd hoped
it would.).

I can elaborate if anyone would like. I think I have the materials (aside from the figures) necessary to replicate this custom.
I used the pictures of the matching Sideshow figure for a lot of the details.