For the details, would it be possible to use a purchased leotard and attach cording with a zipper foot to make the vein-y look? I know what I'm talking about, but I'm not sure I can explain it- anyway here goes:
Outline on the wrong side of your leotard a line of detail that you want to work on.
Then lay a piece of thin cording or thick string or even kitchen twine maybe, over your drawn line. Use a couple pins to keep it in place. Fold your leotard over and topstitch from the right side, using a zipper foot, as close as possible to your cord. Then repeat this for the next detail you want to work. Repeat as often as necessary.
It works in my head- but a lot of stuff that works in my head doesn't work anywhere else.