It wont work.
The baby will need to start in a rear facing car seat, and then move on to a front facing car seat with the 5 point belt, before moving to a booster - so you are looking at 2-4 years at least until you move to a third booster.
These baby car seats take up a little more space then a booster seat. You wont be able to get the baby seat in, alongside 2 booster seats - unless you really shift them along so the edges of the car seats are touching the doors!
Safety first mate. I would just get a bigger car if I were you. Your family is the most important thing, and their safety comes first. Dont risk it by trying to make car seats fit in where they arent supposed to
