2 doors, that's tough with a baby. My family's secondary auto is a 2 door truck with a tiny bench seat. Getting carseats that fit back there a pain in the ass. If you have the van, I think the prius is a good second choice. If the car is really reliable as reviewed, I wouldn't worry too much about the warranty, but you can find some used car places that have some sort of short warranty. You'll probably pay more for it, though.
I don't believe in getting cars for occasionally hauling around more kids. It's like getting a house with a guest bedroom, IMO. Just not necessary.
On rear facing- I just turned my youngest to FF months after she turned 5. Yes, I had a rear facing kindergartener. The reason we RF longer is because it is safest for protecting the spinal cord, given the probability of frontal impact crashes. The shell of a RF seat can absorb much of the impact of the child in a frontal crash, much more than the restraints of FF seat.
Kids spinal columns are not completely ossified until much later than toddlerhood. The spinal cord can rupture with a 1/4 inch stretch- by rupture I mean break, and that means paralysis. Until the vertebrae of the spinal column are ossified, they vertebrae can give as much as 2 inches in an accident. Basically, the bones do not protect the cord well enough until ossification is complete. Yes, you can argue the chances of getting in an accident, getting in an accident that is that bad, etc. But I'd rather not take chances when it comes to stuff like this.
To be clear, I am not a helicopter parent. I let them play and climb and fall and wave sticks around each others' faces. They need to learn to manage risks. But my younger brother is paralyzed (winter sport accident at age 17) and being paralyzed is not easy. Needing an in home care giver can be a hassle. Not being able to be completely independent is very frustrating. Living on social security and not being allowed to have any savings sucks. (Assets in excess of something piddly like 2K results in non-payment of SS.)
