Yes, Rajon Rondo and Mario Chalmers are the best two options for the Cleveland Cavaliers. Rondo and Chalmers are both incredibly talented basketball players. They have also proven themselves to be team players. This is a trait that is needed more in the world of sports. They should be very successful.
The Cleveland Cavaliers are a good team, but lack a deep bench. By adding Rajon Rondo and Mario Chalmers, they will strengthen their team considerably. The two may not look like that significant of an addition to the team on the surface, but they both bring much needed talent to their positions.
Rajon Rondo has exceptional talent, but he's a locker room-killing presence and makes every team he goes to worse. Maybe Lebron could keep him in line because they don't really need him to be good, but that's not a bet I'd want to take. Mario Chalmers is a better option, as he can more easily fit onto an already existing team without the drama.
Both of those players are weak, and Rondo in particular has a lot of character issues as a person. The Cavs already have the best player in the game in Lebron, and one of the best point guards in the game with Kyrie Irving. If they need role players they can do better than Rondo and Chalmers.