Dear Dr. Schmid,
I must admit that I find aspects of said genealogy to be rather enigmatic.
For example, as I'm sure that you're already aware, Hoori gained a spouse from that visit, Toyotamabime, but, to my knowledge, her maternal origin is never mentioned. Matters also get more complicated when you factor in the debate over the meaning of the term 和邇.
Toyotamabime's physical transformation, the taboo of looking, and several other factors, remind me somewhat of Ōmononushi's mythology, but here he appears to take the form of a serpent, rather than a "shark".
Further reading:
https://kojiki.kokugakuin.ac.jp/shinmei/toyotamabime/https://kojiki.kokugakuin.ac.jp/shinmei/omononushinokami/
Leonardo Wolfe