The amount only affects the payroll, however ownership wants to define that. It does not affect the Bulls salary cap or luxury tax.
As far as what the Lakers are thinking, who knows. They just drafted a power forward in Julius Randle, and have since re-signed Jordan Hill and just earlier today added Ed Davis at the minimum. With the way Boozer's declined, you can't even figure if this is a win-now or tanking move, heh.
But fear not: he cannot be traded back to the Bulls.