In Ranma 1/2 Season 1 there are both English and Japanses audio tracks, but the end credits for each episode only list the English cast.  On Disc 4 under bonus features, the entire season's cast list (including Japanese cast) is listed.

Since the Japanese cast isn't listed in the end credits would I mark them as uncredited and cite the "Bonus Features on Disc 4" as the source?  Or would I just list them normally and cite the source?

I agree definitely uncredited... as the rules says to take cast/crew from credits only with uncredited cast the only exception listed of course. But at least you have a very good source in the disc itself for the uncredited cast.