SeatGuru's seat map is incorrect, so I suggest you refer to the official IOJ 77W seat map published by NH that I've linked to in the master thread. (You did read the master thread first, right?)

As has been mentioned before, the presence of the lavatory is not a huge issue due to the nature of the seating (with dividers and other barriers to block some of the view and the sound). It may get crowded with people queuing prior to landing but this tends not to affect rows 5 and 6 in my experience.

Also note that the mini-cabin will fill up before the aft business section(s), so if the load is light that day you might prefer sitting further back with fewer fellow passengers.