I can't think of a better system for Jeff Green then playing with Mike D'Antoni and having Dwight Howard have his back. He would have to play PF and he would be one of the most athletic PFs as far as running the floor in the game. He also wouldn't have to really worry about his play on Defense because D'Antoni doesn't prioritize Defense anyways. He could spread the floor and run the floor quite well for LA in that system,
Bass would give them a solid backup big that can also space the floor and run the floor pretty well. Lee would be a very good backup for Kobe. He would be like Raja Bell 2.0 under D'Antoni, but just more athletic and without the mean streak.
Pau would give us the most skilled front court in the entire NBA. He would work wonderfully playing inside with KG outside. KG would be great for his defense. Pau could easily play off of all of our big three and also be a fantastic rebounder for us.
I honestly think from a pure basketball standpoint that Bass, Lee, and Green for Gasol is a pretty good trade for both teams.
Yet, financially I am not so sure, especially for LA. I think they really value having Artest, Kobe, and Pau all coming off the books the same season.