He defends takedowns by managing distance well and being in good positions. He's not known for a good sprawl or anything. And he has great cardio and a great chin, like Tony. He's by far the best striker of the three (Max, Tony, Khabib).
However, unlike Tony, he's not especially physically strong or a wrestler, so if Khabib can repeatedly get ahold of him, he's going down. And he isn't anywhere close to the threat Tony is on the ground with elbows and subs. He's also not great at finishing fights quickly; he typically requires accumulation of damage.
I think Tony is the tougher fight for Khabib, but I'm not ruling out Max's chances of winning. He needs to keep it on the feet most of the time and out strike Khabib, and in the process, wear him down and make him gas to win a decision or finish him late.