According to HKFA/webpac that three persons are one person:
Yung Yung:
http://www.hkmdb.com/db/people/view.mht ... ay_set=eng
Doreen Chien:
http://www.hkmdb.com/db/people/view.mht ... ay_set=eng
Chin Yung Yung (has a image at the database):
http://www.hkmdb.com/db/people/view.mht ... ay_set=eng
Opinions?
I don't want to merge them without another proof.