So the sudden lack of detail in this development kind of bummed me out.
I thought so too initially, but if you look at Eli and Ian's talk in ch 290, a lot of this is foreshadowed. It's Eli's first meeting with Ian, but she knows Ed already and Ian implies Eli's visited Japan before.
Wait...when did Elisha get screamed at by Honokas sis?
Kaoru didn't yell at her, but she wasn't very friendly. They talk in 288 and 290.