We know what Usama Bin Laden & Ayman Al-Zawahiri look like but:
ABDELKARIM HUSSEIN MOHAMED AL-NASSER
ABDULLAH AHMED ABDULLAH - Aliases: Abu Mohamed Al-Masri, Saleh, Abu Mariam
MUHSIN MUSA MATWALLI ATWAH - Aliases: Abdul Rahman, Abdul Rahman Al-Muhajir, Abdel Rahman, Mohammed K.A. Al-Namer
ALI ATWA - Aliases: Ammar Mansour Bouslim, Hassan Rostom Salim
Based on just these names of the top most wanted you can see why the Intel guys have so much trouble sorting out the passenger manifests of these planes in question. Abdul, Ahmed, Abdullah, Mohamed (spelled many ways)and more.
BTW FWIW, I heard this morning they are getting close to the missing passenger from Christmas Eve. Last night Arnaud de Borchgrave said the name is A.H. Hai with the first name Ahmed is the one from Afghanistan.