All right, I gave in and ordered the hakama/kataginu pattern from Folkwear. I could almost certainly have figured out how to make the things just from photo references and the line drawings some web sites show with the pattern information, but that requires thinking, and if I get stressed out with waiting till the last second for fabric, or something else, which seems likely, then I won't want to think too hard, and a nice, safe pattern will bail me out. So I dropped the $15 plus shipping.
For my own reference, I shall now list some resources I'm likely to want to look at while designing the bottom layer of the costume.
*Oriental Costumes, Their Designs and Colors, by Max Tilke - scans of the book
*Articles on Costuming, including a section on Asia
And I even requested a book from the library, on sewing Japanese clothing. For all I know, it'll contain instructions for making a hakama and kataginu, but the Folkwear pattern got ordered in case the interlibrary loan doesn't come through in time.
Oh, and in case anyone happens to read this and wonder why on earth I'm ordering Japanese stuff for a Chinese pirate costume, she's a bit of a fusion character, and anyway, note the pirate part. She can commandeer other people's clothing if she likes. ;)