about note #4
I believe when they refer to the departed head of 本鬼頭 as 太閤, they’re (reverently) comparing him to Toyotomi Hideyoshi.
The barber was talking about how things are dicey for 本鬼頭 following 右衛門’s passing, with his son insane and his grandsons both soldiers not back from war. Rather similarly, Toyotomi Hideyoshi was an important Sengoku-era leader whose clan’s power crumbled following his death. He nearly unified Japan, but his heir was defeated at the Battle of Sekigahara by Hideyoshi’s former ally/rival Tokugawa Ieyasu (家康), who subsequently founded the Tokugawa shogunate and ended the Sengoku period.
I didn’t know about 淀殿/淀君 (seems like an old/new name writing variation or something), but apparently, she was a wife of Hideyoshi who played a role in resistance against Tokugawa with her son (the heir who was defeated).
So I suppose the comparison means that the 本鬼頭’s position of power is a precarious one! Perhaps even more so than the Toyotomi’s clan’s was following Hideyoshi’s death, Toyotomi had 淀殿, but here, 分鬼頭 has the equivalent of both 家康 and 淀殿!
Sorry I can’t help on the grammarish questions! Those are (even) harder to answer when not plugged into the book’s writing style at the moment!