The Gothic Princess' base is probably a regular Haruka's body.
All of the others used a Tohsaka Rin body as the base, I used a Rin as the base for my
Punkish-Gothic Haruka as well so I can recognise the similarities of the modified figures at the very least.
For the head I'd personally use a Miki head, Miki's hair isn't glued to the figure, and afterwards make some new hair from scratch.
Also, I do believe they're putty resculpts.