At the graveside of Daniel Hutton, the grave said "1st Lt" followed by "US Navy." There is no such rank in the US Navy. It is a rank in the Army, Air Force, and the Marine Corps. The equivalent rank in the US Navy is Lieutenant Junior Grade (LTJG).
When Cooper is watching the video on the laptop on Reddington's jet, the file path in the window's titlebar starts with "E:/System/." DOS systems (e.g. Windows) that use lettered drives like this use backslashes (\), not forward slashes (/). File paths in Unix systems, such as Mac OS and Linux (which use forward slashes), always start with a slash.
In other words, the path should either start with E:\System\ or /System/.
In other words, the path should either start with E:\System\ or /System/.
Katarina makes sure the babysitter quits, so she can gain access to Keene's apartment. Which is useless, because they already had access when they placed the listening devices.
Katarina watches over Agnes, but it is completely unknown how she got into Keene's apartment.