I don't like the basilisk skin replacing the boomslang. Boomslang skin is one of the two main ingreadients of the potion, perhaps the key ingreadient, in that it has the ability to change its colour to fit with the background - like a cammilion. Which is probably what you are looking for in a potion meant to change your apperance.
In fact, back in the early Harry Potter novels, JKR did her research well, and it showed in her potion recipes, too. So all the ingreadients are real stuff and have something to do - if only by associative reasoning - with the desired effect of the potions they are used in.
I went and checked each and every one of those ingreadients she mentioned in several books, and they all made sense if I could find the right herbological, botanical or mythological refference, except one that baffled me, as it seemed JKR made it up, and that one, too, was more of a word game on something that DID make sense than some nonsensical jumble of vowls so many fanfic writers come up wioth for potion ingreadients and Luna Lovegood's little pets. So I know what I'm taliking about. [Did it all for a story I wrote in which Snape's lacking teaching skills come back to haunt him when Harry tries to summon a bezoar to help Ron in HBP, but not knowing the difference between a regular bezoar and a rasphondel, ends up bursting Snape's inners open violently...]
Anyway, basilisk skin, on the other hand, is nothing like boomslang skin, and has nothing to do with any form of transfiguration and morphing, I can't see any use for it in polyjuice potion, sorry.
s.a.c.