1. Bonucci plays CB in the 3 man defence - flanked by Barzagli and Chiellini.
2. Apart from a very small handful of games, Lichtsteiner hasn't played CB at a high level.
Which leads to:
3. Defensive play is entirely different at fullback as compared to centre back, so any theories you may have regarding defensive solidity based on watching a fullback and a centre back should be taken with a massive grain of salt.