Hi Jamie,
We just went thru this, but not because of #3. My son is in the giant Britax Regent for added safety and my newborn would not be able to fit in the middle of my Murano. Plus, we occasionally car pool other kids to school and even fitting a booster seat in would have been tough, unless you had super skinny hands to fit in between to buckle in. We ended up buying the GMC Acadia - a SUV with the same dimensions as a mini van. Granted it doesn't have as many conveniences as a minivan but we love it and it fits 8 with the ability to fit three car seats (one huge, one infant and one booster) in one row. I just couldn't do a minivan. I always feel like the driver seat will tip me and eject me down the pointy hood. LOL!
Good luck