I think he got his 4th point in the second quarter when Luka was sitting. He had the 3 that gave them the lead to close as well. Obviously they are better if they can play together and someone, anyone covers defense. But it's way too early to proclaim anything and if Luka freezes him out I don't see him continuing with the Mavs.
Pretty much. Obviously, one of the two will be on the floor at all times, but, equally obviously, they'll also need to figure out how to share the floor for half the game over time. There's a reason Kyrie has played for 4 teams, skilled as he is.