100%They will see each other. Here is the reason.Because When she requested Zeniba to tell her about How to save her Parents & Haku She gave her a Hairband,Magical one. It helps someone to recognize the person/spirit in past.So She say You cant forget someone in past even if you cant remember it.Because of the Hairband she Recognized her parents were not present there.&That will Solve mystery that If Haku and Chihiro will meet Even if chihiro Forgot all memories in Spirit realm,She will recognize Haku same as She recognized her parents.Even Haku knows that thats why He promised to Meet again. ❤️❤️❤️