The only seat I have put in the car has been our travel Cosco seat in the middle row. It installed very easily but it's not the comfiest.
The 6 year old is 53 lbs. And the 4 year old is about 35 lbs. I'm sorry I don't know heights. Not sure on the infant yet, still pregnant.
I have been looking at the Oobr for the 6 year old. She has not used a booster before but it would be great if she could buckle herself in the 3rd row. I was looking at the Foonf for the 4 year old. I have Britax seats in the primary kid hauling vehicle, a 2021 Odyssey and I like them but they seem very bulky for the interior of the Tesla.
Hi Ashley. Generally Clek seats are really nice seats, but I think if I were in your shoes, I'd skip them, unless you want the Liing for the baby. The Oobr has a tall booster base, which in combination with the low roof line of the 3rd row puts head injury into the risk zone. The Nuna Aace has a shorter bottom, so it won't sit as high. It also has rigid LATCH like the Oobr and can become a backless booster when she outgrows the back.
I think your 4 yr old will quickly outgrow the Foonf by height; most kids don't make it much past age 5 in that seat. Unfortunately, there's a real scarcity of carseats that work forward-facing in Teslas. Nuna seats fit well (fairly low top harness slots, though), as do most Graco seats. Britax simply doesn't work forward-facing, though I seem to recall the One4Life being OK (I need to stick the seat back in my car). The Chicco MyFit doesn't work. The Chicco Fit360 rotating carseat fits like it was made for the Model X and the Evenflo Revolve360 seats fit nicely too.
The only infant seat I haven't loved in the Model X has been the Nuna Pipa with the original base. So if you look at a Pipa, just make sure to look at a model with RX in the name.
I have installation videos on my YouTube page if you want an idea of how some seats fit:
youtube.com/carseatsite.
HTH!