OK, so I have been experimenting with car seats and booster seats in the Insight. Here is a picture of a Chicco Keyfit 30 infant seat, a BubbleBum travel booster, and an Evenflo Big Kid highback booster in the back seat. VERY cozy. My girls were able to get into the boosters, but it wasn't easy and my 9-yr-old just barely fits between the other two. If her hips get any wider that would be the end of that. So I don't know what the plan is. I haven't tried replacing the infant seat with the convertible seat we already have, but I think that will be even worse. We are going to get my husband an SUV that will fit everyone comfortably - this week I want to go take a look at the 2020 Santa Fe. Then maybe we will just have to make do for a while with only one car that fits everyone and only use the Insight for all 3 kids when absolutely necessary. When I eventually go back to work and we need two cars set up for the kids, I will have to get something bigger.