Yes. In fact, you can just take a brawl snapshot, convert it to .jpg and do the same thing.
As for the threads and texts. Here's the CUPASH thread:
http://kittycorp.proboards.com/index.cgi?board=ontopicdiscussion&action=display&thread=309 (must register to view the topic)
hope that helps.
EDIT: Although there isn't a thread at the moment. There's a somewhat easier way to know which tga belongs to which pcs. Go to smashwiki and look up an SSBB character. Then look at their costume gallery. The tgas are set up in that order and if you know which texture belongs to what costume, then it gets easier.
So for Captain Falcon, it would be:
captainfalcon1 = fitCaptain00
captainfalcon2 = fitCaptain04
captainfalcon3 = fitCaptain01
captainfalcon4 = fitCaptain02
captainfalcon5 = fitCaptain03
captainfalcon6 = fitCaptain05
if i ever have any freetime, i could do this unless someone else does before me.