Regard to LeBron James, he continues to play, most of the games he manages to have a good score, in others not so much, unfortunately he cannot carry the team on his shoulders as he did before, and it is clear that he needs help, especially AD to get the Lakers to the playoffs and perform well in this stage of the competition!
Lebron is not the main man anymore. Though he can still contribute to the offense, he is not that much anymore in defense. He is not as intense as he was when he was in Miami or in Cleveland. AD is the main man of the Lakers right now but his availability to play prohibits him to carry the team. IF Lebron is not bringing too much income to the Lakers organization, I think he will be out already. Let's see how far the current roster will take them and how long the Lakers will stick to AD and Lebron if they do not bring success to the Lakers.
I don't know. But I believe LeBron James is still the Lakers best player.
One factor that I think is relevant is that, he is not as enthusiastic with the team, like beforehe, day after day it seems that the level of the Lakers is decreasing and I believe that this is putting LJ down.
AD is greatly missed, and I have no doubts about that. An interesting point is that, if LeBron James suffers an injury, the Lakers still have a player who can replace him (in the worst case, adapting, maybe Westbrook, Walker, Reaves, Beverley and others). Now if AD gets injured and needs to stay out (and this is happening), unfortunately the Lakers don't have a player that can replace him, because he is an extremely high quality PF/C and an excellent defensive player, and the reserves or others Lakers players are unable to resolve their foul.