Curtis is out there somewhere, but probably left when HS took over CTU. Surely he'll show up somewhere.
Aaron is either taking a dirt nap OR he left his cell phone there for Martha to find.
And I think you're right. Henderson doesn't have the only copy of the recording. Jack let it go too easily. He knows Audrey ain't worth it.
If they kill Aaron, I'm going to be very, very irritated.
That's what I'm hoping, so she'll start getting suspicious of her slimeball hubby.