Responses
I think the spirited away friend is actually Yukito. He calls him Yuu in his flashback and he doesn't remember his face well. Yukito also said that "It's been a while" when he was called by his first name. So I think Yukito just didn't realize it at first but remembered Imasaki later and why he was sure that he can see people's futures.
But that kinda contradict his good luck no? Cuz he went missing
what actually happened to the spirited away friend though? we never really found out how or why the kid went missing, i was hoping they'd explain that...