"Those five Iranians, who were arrested in the northern city of
Those two members are these guys, Chirazai and Davari, who were arrested in December and do not belong to the group of five detained in Irbil in January. All we currently know about the Irbil detainees is that they aren't official diplomats and that the US is claiming they are members of the IRG involved in facilitating attacks on US forces.
As for Khalilzad saying last week that 2 of the 5 belonged to the al-Quds force, I have no idea where Krane & Reid got this, and I don't think it exists at all. I have found him saying that the five belonged to the Revolutionary Guard and that "some" of those five belonged to the al-Quds force. As Borzou Daragahi notes, Khalilzad stated he was going to reveal the identities of the detainees today in a press conference (which has been postponed).