>>88133141this, for sana and ame they didn't really say any huge graduation baits out-loud or keep baiting the topic. they were just quiet for a while and then went "welp I'm gone bye." gura is the one very clearly showing this pattern but the thing is, people like ayame and shion are still there on the JP side, it's no guarantee it'll happen soon (or even at all) if they become very distant and quiet, just that it makes them seem more likely than someone who is firing on all cylinders daily like koyori.
for nijiENs, I don't recall people were thinking pomu was gonna graduate since she just never talked about it and people were always going "she's literally a real niji otaku and mito is her kamioshi she's never going anywhere" etc. the predictable graduations aka vivi and kunai are because anyone with eyes could see they cratered in debut since they have come about after the public basically decided that nijiEN's time as a viable corpo branch is basically over.