jjbond:
In Group 2 you've got Mike Solomko on the left, and in Group 3 you've got Hidefumi Kawamura (Hiroshima) on the left and on that four player card I recognize Tadashi Sugiura (Hall of Fame pitcher for the Hawks) on the lower left.
Its a bit hard to read the kanji on the other ones without higher resolution scans.
Adam:
For sumo cards you should contact Ryan Laughton (AKA Sumomenkoman) who wrote the guide on them (and is a great guy). He has a blog here:
https://sumocards.blogspot.com/