Lugano v Alex really depends on how Juve are going to play.
If Juve were to defend in a compact fashion and focus on organisation, Lugano is the man.
If Juve are going to go out to dominate in games, playing attacking football, more of the defending will be counter attacks and defenders having to play one-on-one against a forward, often in large spaces. Alex would be more suited to that, while Lugano would have his lack of pace exposed and be likely to pick up a lot of cards.