The two new names are 朱陽 密 (Shuyou Hisoka, like a fancy word for sun + secret) and 四色 典子 (Yotsuiro Noriko, four colors + ceremony). Each of their family names sounds like the start of a Cthulhu Mythos term in Japanese, with their given names using kanji from the latter half.
Specifically: De Vermis Mysteriis (Mysteries of the Worm) and Cultes des Goules (Cults of the Ghouls) respectively.
Kikyou’s t-shirt is a reference to a famous (infamous?-ly terrifying for kids) Gegege no Kitaro game on the Playstation. The main villain in it was a youkai named Nikuningyou (肉人形, Flesh/Meat Doll) who was extraordinarily creepy for the time. (I don’t recommend googling it as a lot of unrelated 18+ stuff will come up, but here’s some streamer I’ve never heard of doing the final boss fight if you want to get a feel for the vibe.) (Maybe Kikyou feels a connection, as a doll haircut haver herself.)
