If you get a used one from a person you know (and presumably trust with the life of your child) these are the questions you should ask
1. What is its date of manufacture? Is it expired?
2. Have you called the manufacturer with the model number to see if it's been recalled?
3. Was it ever in a car accident, even a minor one?
4. Did you ever soak the harness in water, or put the harness in a washing machine or clean it with anything more vigorous than a baby wipe or warm washcloth?
5. Did you ever check the seat while you flew on an airplane?
If it's expired, recalled, been in an accident, been checked on an airplane, or had its harness laundered, it's no good and shouldn't be used.
Honestly, I'm going to strongly recommend you avoid all three. The Peg Perego infant seat is a nightmare. Parents like it because of the brand name recognition, but it's heavy, doesn't install well in many vehicles, is outgrown early and doesn't fit newborns well.
The Graco Snugride 22 does not fit newborns that well and is outgrown early.
The Mico fits newborns reasonably well but is outgrown early.
Honestly, compatibility with a stroller is not a great criterion to use to pick a child restraint. Child restraints are life saving crash devices that you need to work PERFECTLY in your situation, if you need them at all.
Car seats that fit newborns well, install well in a large cross variety of vehicles, and aren't outgrown supremely early include: Chicco Keyfit 30, Graco Snugride 30 or Graco Snugride 35, the Safety First Onboard Air 35, and Combi Shuttle 33 or 35. You'd do well with any of those seats.