Ranma 1/2 Memorial Book gives Shampoo's name as:

Sha n pu <vowel extension mark>

Henceforth, I shall give her name as "Shampoo" when normally addressed
(English translation stuff) and Shan Puu as her formal Chinese name.

The graphems "sh" and "x" are different sounds in pinyin. It DOES make a
difference which one you use.

And actually, "shan"(first tone) is the correct use anyway. Pu is better.

Any objections?  (Except that it's a little late to fix Xian-ko in
Scarlet Spring)

Not for that, but you might want to reexamine your use of "Xian" in "Xian-ko".

Shan Pu: "She with breasts like mountains." (one interpretation, anyway ;)

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