From 2003-2015 the Pilot was only available as an 8-seater (3 seats in the 2nd row, 3 seats in the 3rd row). For 2016 the Honda Pilot is now available as a 7-seater as well (2 seats in the 2nd row, 3 seats in the 3rd row), or the usual 8-seater.
The 3rd row was changed for 2016 – and 3D & 3C are now much narrower than before. 3C is now too narrow for most car seats & boosters (but will fit the Harmony Youth booster) – so best to consider the 3rd row as having 2 seats (3D & 3P), not 3 seats. The 3rd row seat is also very low to the ground – making it a really awkward seating surface as even at 5’1″ my knees and thighs were completely off the seat cushion. This was not only awkward, but also not so safe as the lap belt came up into my belly somewhat because of how high my knees were. 
The center seat belt for the 2nd & 3rd rows comes from the roof.
2009 saw the addition of lower anchors for the 2nd row center seat. We have not counted them as the lower anchors for 2C overlap the seat belt for 2C. The other issue is that the innermost lower anchor for 2C is too close to the innermost lower anchor for 2D. What this means is that you can not secure 2 car seats side by side in 2D & 2C with both using the lower anchors because there isn’t enough physical space to do so; the solution is to install one of the car seats with the lower anchors, and the other with the seat belt to get seats side by side in 2D & 2C.
If you need 3rd row access AND need a car seat in 2C you’ll need to install the car seat in 2C with the lower anchors, not the seat belt. If installed with the seat belt, the car seat in 2C will overhang just enough into 2P that you won’t be able to move 2P for 3rd row access. The lower anchors in 2C will position the car seat a smidge towards 2D and will allow movement of 2P for 3rd row access. If you need car seats in 2D & 2C and 3rd row access, pick very narrow seats for 2D & 2C. The IMMI Go in 2C + rear-facing Clek Foonf or rear-facing Cybex Aton2 in 2D is a good combination we’ve found (the 2nd row of the Honda Pilot is the same as the 2nd row of the Acura MDX as shown below).
This vehicle accommodated 3-across in the 2nd row very well as it had a very wide, relatively flat 2nd row bench. Surprisingly the newer model years were NOT so favorable for 3-across as the 2003-2008.
