I'm confused on the name change bit. In the original post you mention that you need to do a name change after you file your taxes so I didn't think you had actually changed it yet with the US or state governments. If you have to get the new passport issued in the new name you should get to keep the old one. You also can try calling the airline to see if they'll change it for you, though chances of that are lower than not.

And we're looking for 3-4 days of stuff to do not in IST. We were thinking of heading in to the north central Anatolia region to see some of the ancient ruins but aren't sure since the infrastructure there seems rather limited.