What then is the status of Saotome sensei and Seagal sensei? The list was quite extensive so I may have overlooked your answer.
I don't know that much about the history of the ASU, but I think Saotome was a Hombu shihan in Japan but his move to the US was accomapnied by a break with the Aikikai. He was accepted back into the fold sometime shortly after George Ledyard got his 4th dan. (Is this about right George?).
As far as Seagal goes, he was once a "cultural shihan" in Japan due to his rank and status as an instrucor. I don't think he ever received any kind of certification. As far as I know he no longer has an active dojo nor is he part of any aikido organisation (recognised by the Aikikai or not). Some of his former students are still active in the Aikikai. Larry Reynosa's organisation, the Makoto Aikido Kyokai, is a recognised Aikikai organisation.