Loading and unloading kids and seat placement

[walnutgold]

I have six kids and another one on the way. We have a Nissan NV 12 passenger van. We would like to remove the backmost seat for storage space until baby 7 arrives. Which seats would work best next to each other? What would be the easiest configuration of seats to load and unload kids?
These are their latest measurements:
DS1(8)- 60lbs, 55", 18" shoulders, HBB (is willing to ride harnessed if it's too hard to buckle his booster between seats)
DS2(6)- 36lbs, 40", 13.5" shoulders, RF (needs to ride RF due to low tone and health issues)
DS3(5)- 43lbs, 46", 16" shoulders, RF (prefers to ride RF, but can ride FF)
DS4(3)- 31lbs, 37", 14" shoulders, RF (can ride FF is ABSOLUTLY needed)
DS5(nearly 2)- 25lbs, 29", 10.5" shoulders, RF
DD1(nearly 2)- 27lbs, 30", 11" shoulders, RF

Seats we have to work with: Recaro ProBooster, Graco Extend2Fit(2), Chicco NextFit, Graco Milestone(2), Clek Oobr, Graco TurboBooster, Britax Frontier, Diono Radian RXT(2), Evenflo Maestro, Evenflo Sureride, Graco SnugRide 40(2), Cosco Apt 50, Graco Nautilus, Graco 4Ever, Graco Tranzitions, Harmony Defender

DS1 and DS3 are the only ones who can unbuckle themselves without help.

 

[ketchupqueen]

How do you have the other seats configured? Which seats are easiest and hardest to reach?

 

[walnutgold]

In terms of vehicle seats we have two rows of three and one row of four and we would like to get rid of the row of four.
In terms of current car seat configurations DS1 rides in a Recaro ProBooster in one of the inner seats in the backmost row. DS3 rides outboard in a Graco Extend2Fit, also in the backmost row.
DS2 rides in a Graco Extend2Fit in the second row on the side closest to the door. DS4 rides in a Graco 4Ever on the opposite side in the second row.
DS5 rides in a Milestone closest to the door in the first row, and DD1 rides in another Milestone on the other side of the first row.

 

[bnsnyde]

We have 6 kids and load/unload each trip (ages one to ten), so we went for easiest placement among other reasons. But we have the Odyssey. I can see how you need the vehicle you do!

We had 6 carseats up until a few weeks ago when my 10 YO passed the 5 step test.

I can never get my toddlers to climb in, so I like them outboard.
I don't like baby in middle since infant seats get heavy BUT I have my 15 month old in the Graco 40 in the middle and this works. I load it with my leg (constant bruise on the knee but better than a hurt back).

I tend to put older kids in back. My seats are in the signature. Keep in mind mine are super tall though. At age 2.5 I had trouble keeping my one son RF as he is like 99.9% for height and solid.