This is almost exactly what I have done to my 110, as I had the requirement to be capable of a 3rd row that can accommodate booster seats. I just built drawers, and my middle row 60 bench can be fitted as a 3rd row in the cargo area. factory in this space was four flip up inward facing jump seats that were removed long ago. My 3rd row bench can flip forward or easily be removed with quick disconnects.
The seat doesn't hold anyone in during an impact, it is the seat belt. I have 3 point retractable harnesses I added, using seatbelt anchors (seat belt planet) at all 3 points for a solid connections. For the middle/center connection that holds the female harnesses, I used a 1/4" welding plate that is part of the drawer box, passes through the divider section and anchors to the floor. I can connect the center buckles to it on top of the box with a shackle, making them long enough to be used and easily removed when the bench is flipped forward to use as cargo.
To clarify, my middle row was a 60/40, so the 60 went to the 3rd row, and I purchased a used additional 40, so my middle row is a 40-fridge-40. All those seats are on quick disconnect, so I can switch back to 60/40 easily when I need to.
Overall, I'm very pleased with the modularity/flexibility of my setup.
https://www.seatbeltplanet.com/seatbelts-and-accessories/hardware-kits/