Am looking at flights to SEA NRT and row 17 seats D/E are blocked out, also on the return flight. Any specific reason for this, I know they could be booked but seems strange that these are the only two seats on the entire flights that show occupied.
Assuming the 787, those are blocked for special needs pax. An agent can assign them to you but that can be overridden if they have a passenger who actually needs them.
So the aisle seat which is not blocked F would be ok, to book, or can the agent take that one away also?
They can do anything they want. It is less likely if it isn't flagged in advance as a special needs seat, but seat assignments are not guaranteed. I'd also say that a regular E+ seat is better than the bulkhead in terms of ability to stretch your seat forward. Worse in that people inside have to climb over you to get out and the person in front can recline.