Recently took a slightly longer trip in the CX-90 that utilized all 6 seats, with the two captains chairs having car seats. Just wanted to drop some feedback related to it.
It is possible to get into the rear with a car seat still in the second row by moving up a front row seat, then sliding the second row seat all the way forward. However, it is not ideal by any means. The above head handle is not really visible when getting in, and is really needed to get in to the third row.
We had smaller adults in the rear who commented that the seats themselves were comfortable, but the feeting arrangement was somewhat awkward. This is partially driven by how far back the second row is with car seats and was easily adjusted on the return trip. I would say with normal second row usage average sized adults (5'5" - 5'10") should be at reasonable comfort levels in the 3rd row, however, this is not a road tripping 3rd row. I feel like some of this feedback should be obvious, but just wanted to relay real world usage. Our intended usage was centered around a four person usage with the ability to carry some additional family as needed from time to time so YMMV.
We ran into traffic on the way home, and after the car heat soaked, the cooling capacity in the rear diminished (its a separate cooling system from the engine). But this was also probably partially my fault for not manually controlling the system sooner. The front was still cold, and I adjusted temps up after I cooled down and this pushed the rear higher.
Even with the MPG hit from hitting all the traffic, the overall trip average at 70-75 mph was 29 MPG. Probably would have been just over 30 had we not hit the traffic.
I hadn't needed to use the ventilated seats up to this point, and have nothing to compare them to, but they were fantastic. Cooling capacity on the back was almost up to my shoulder blades, and even with heat soat in traffic was doing a fantastic job.