Kei's Kars does not have an Ultimate Lifeform version, as far as I know. Also, while this character certainly is overpowered, he's not a cheap char. Great for boss battles.
UPDATED: Yukako Yamagishi by Heal the World. Her Idle stance as well as some of her other sprites have been updated with this look:
Other than that, she still plays the same as before and is still pretty rough around the edges but still playable
EDIT: Slightly updated AI as well. Looks like she now can put up a fight, too. Still a very weak AI, but it's better than just standing around doing nothing like her previous version xD