I bought some figures from FTCs sister site https://www.classictvtoys.com/
I'm documenting my path so you can take the shortcut if you want the figure added to your collection.
I misplaced my original project, so I'm going from memory, and some of the pieces were purchased a second time (Arrgh)

The goal:
Have a female 8" figure wearing the Robin TV series costume, but with a Molly red head with shorter hair.
Items you need:
Female body
Red hair female head
Green gloves (female)
Green boots/shoes (Robin)
Robin Body suit
Robin Mask
Robin Yellow cape
Robin Utility Belt
custom Backing card for blister pack
blister pack
Optional custom box for figure.
First step: Body.
I started with the standard female body, but I quickly found out that the Robin TV costume doesn't fit it well, so I went with the new S type female body and the robin suit fits as it should A note here: The website has changed from when I started a couple of years ago. You used to be able to order the costume complete sans body, now you have to piece it together.
That S type body is the way to go for Catwoman and Batgirl if you want a better looking figure.
So my order arrived, and I realized I forgot to order gloves, belt and cape. I did order the shoes and costumer. I ordered a red haired doll head with light red hair. I just reordered those parts.
I played around with a backing card for the blister pack. This is not final, just playing around.