The CIA is not being forthcoming - at least to Congress, but it could be we have Hamza bin Laden, a son of Osama's who may be missing from the compound.

ABC News:

The officials said bin Laden's three wives, who are all in Pakistani custody, said that one of bin Laden's sons has not been seen since the raid. The son was not identified, but Pakistani investigators agreed that it appeared someone was missing from the sprawling compound, the officials said.

Later, however, one U.S. official said there was no evidence anyone was missing from the compound and Senator Dianne Feinstein, chairman of the Senate Select Committee on Intelligence, told CNN that in a recent briefing with the CIA there was no mention of a missing son.

U.S. officials said that one of bin Laden's sons, Khalid, was killed in the raid. It is not known if another son, Hamza, was in the compound at the time of the raid, though his mother is reportedly one of the wives in custody. The U.S. has previously denied the SEALs took anyone from the compound other than bin Laden's body. 

I find it interesting that Senator Feinstein said there was "no mention" of another son by the CIA in their briefing. Would the CIA withhold that info from Congress? More than plausible, I'd say.

None of bin Laden's sons are working in any operational capacity with AQ but that doesn't mean he wouldn't be a hugely valuable source. If he were to cooperate, just being around his father for years would give interrogators clues about AQ that we rarely get.