Fridge Brilliance: The fact that the grudge ends in Fuuta and Kouko's eighth lives in Japan makes more sense if you think their spirits are positively drawn to the land already. The Warring States era was the only time they've ever been able to mutually end their grudge, so they may subconsciously go back because they associate "peace" with Japan. It's also worth noting that they're not on bad terms with each other in Showa 91.
Strawman Has a Point: Fone does have legitimate points against trusting/helping Kouko, such as her violent temper when it comes to Fuuta, her attempts on his life, and her inability to let the past go. However, the thoughts are portrayed as the ramblings of a vengeful and hypocritical ghost and are mostly waved off by Fuuta.
They Wasted a Perfectly Good Character: Compared to Fuuta's other past lives, Fuuko gets considerably less focus and characterization. Her life beyond her teen years and how she and Kousuke died are never revealed. Her only major contribution to the story is her encounter with the aliens and the net that captures Fortuna.
Woolseyism: The joke about Iwana pressing Kajirou's buttons by pronouncing the ji in his name is a little confusing without context. Kajirou dislikes the ji character because it can stand for "second/next", making it a reminder of his Always Second Best nature and his status as the second son in the family. An English scanlation rectified this by having Iwana instead refer to him as the "young master", showing she doesn't consider him the real head of his household and implying that there's someone above him.
