i just wanted to share my experience with the 7 seats. we've had ours for a year now. we took delivery aug 2021. my wife wanted the 3rd row and i wanted the performance. guess who won. anyways, in the year we had it, the plan is for our youngest son to sit there whenever my parents come along for a trip. we've used it once for a vegas trip and my son hated sitting back there. there are no vents and although he's short (9 years old), he isn't comfortable.
prior to EVs/Tesla, we looked at toyota highlander and honda pilot because of the 3rd row. we ended up with a mini van. we owned a sienna then an odyssey. we opted for the mini van because the space in the 3rd row from the highlander and pilot was not that big. the model y is no different.
i tried it out before buying it. i sat back there. i'm 5'5". i sat in the passenger side 3rd row. technically, i can fit. the issue i have is the foot room. the rails of the seat in front of me is narrower than the driver side seat because it's 60/40 split. in order for my feet to fit in between the rails, they would have to be sort of on top of each other which is uncomfortable/tight fit. i've seen many youtube videos about "i am over 10 feet tall and i can fit just fine back here" but no one mentions that part. now i didn't pay too much attention since my 9 year old will mostly be back there and i'm always driving. but he doesn't like it.
hopefully you all have checked it out in person and pay attention to not only leg room but feet room as well. we're trading our teslas for MYP and MXLR soon. i just wanted to share feedback. i hope you all get your cars soon. they are great.