Note the pairing of the brackets; the first pair opens prior to 'WH' and closes after 'BC/LL'; the two other pairs seem self-explanatory.
I concur.
Adding, my only smidgen of question was why Hussein is outside the brackets. It left me a small question that someone else in the WH might have been on the phone.
But, I really think the meaning of Hussein and RR outside the brackets is that Hussein is the one who told RR about the call after the fact.