Mu-chan and the yokai talk seriously about mortality and the differing lifespans. It's implied that Jiro was in love with Mu-chan's great-grandmother.
Tear jerking story about Kazuhiko and his late wife Namiko, who happened to be descended from a banana tree spirit, a Basho No Sei hence her green eyes and hair.
Other yokai and food references, in this episode:
Umibozu - Giant sea spirit who portends bad ocean conditions https://en.wikipedia.org/wiki/Umib%C5%8Dzu
Gohei Mochi -Burned rice on a stick with nuts, soy sauce, miso and mirin http://kyoudo-ryouri.com/en/food/385.html
Deitarabocchi - Giant spirit whose footprints make lakes and ponds - Said in the show to become Umibozu when the move out to sea??? https://en.wikipedia.org/wiki/Daidarabotchi
Okari-inu - Dog shaped yokai that follows travellers and eats them if they show tiredness - https://en.wikipedia.org/wiki/Okuri-inu
Betobeto-san - A spirit that follows people walking at night https://en.wikipedia.org/wiki/Betobeto-san