I don't think I've seen a site where this is seen and Gamefaqs has absolutely nothing on this game, not even a movelist.

The only ones that I know so far are these with their endings being described:

Nakoruru
4th Boss - Rimururu
7th Boss - Galford
Goes home with Rimururu, with Galford there for 'safety'.

Ukyo
4th Boss - Haohmaru
7th Boss - Yumeji
Something to do I believe with Kei.

Mizuki
4th Boss - Kyoshiro
7th Boss - Nakoruru
Has Nakoruru as well as the four gems (Kyoshiro, Haohmaru, Sieger and Jubei) and takes over the world.

Cham Cham
4th Boss - Ochamaro
7th Boss - Tam Tam
About to fight Yoshitora who offers her a fruit (similar to Ibuki's Pocket Fighter ending).

Since I'm not sure of the Samurai Shodown collection, I'm curious to know who fights who in the game and, if possible, a small description of their ending.