We've owned two Odysseys over the years and been quite happy with them. Great road trip vehicles. Examining those pics above, it looks like the middle row seats still come out the same way as ours did (?) They're heavy, but being able to remove them is very handy for extra space (I understand that the Sienna middle seats aren't considered removable by the consumer). I recall my second row seats only leaving some recessed attachment points in the floor when they were taken out...
I imagine the third row seats could be removed with a bit of work the same way as on the Sienna. Then you could buy or construct a floor to flatten out the back, with "hatches" to access the recessed space where the third row seats would formerly store themselves - that's significant extra room for a cooler, storage boxes, whatever. All depends on how often you'd want to switch out between three-row passenger config vs. camper with maximum room.
I imagine the third row seats could be removed with a bit of work the same way as on the Sienna. Then you could buy or construct a floor to flatten out the back, with "hatches" to access the recessed space where the third row seats would formerly store themselves - that's significant extra room for a cooler, storage boxes, whatever. All depends on how often you'd want to switch out between three-row passenger config vs. camper with maximum room.