Have you ever watched Cousin's play? He plays nothing like the Warriors system when they are really trying to win. If the Warriors are actually trying to win they should probably play him like they did Pachulia. Start the first and third Q and garbage time and that is it. He actually probably isn't worth much more than the $5M he is making to that team.
As far as Lebron and this years Laker team, there are A LOT of really good free agents coming available next year, including Klay and I think Durant. All the guys the Lakers are signing are 1 year deals. Looks like they are trying to get competitive this year, and next year will be the year they make a push. If the Warriors lose a star or two next summer and Lakers pick up a star or two (both very reasonable) the shift of power in the west could turn fast.
As far as Kawhi, a lot of that depends on how committed the 76ers think he is to signing a big deal with the Lakers in the next year (something the Lakers will have the flexibility to do next summer with their current roster moves). How much are the 76ers willing to give up on what might be a 1 year rental?