Not sure about the first one. Is there a place for a bolt on the folding seat? Will the straps (in rearface) slide down the sides of the seat?

I started with my toddler and one side, baby on the other. Easier to get them in and early on DD couldn't be trusted to sit next to the baby. Now i have them next to each other, baby on passenger side and DD in the middle. This gives some room for a very small person to sit on the driver side back seat or to put kinder bag etc on the seat.