Bron just needs to go from $43m to $34m in order to make it happen. He can even go lower than that to free up more cap space - I think he had to forego $15m or so to join Wade and Bosh in Miami so not out of the realm of possibilities if he really wants another championship run. Plenty of examples of star players taking a lower salary on in the latter stages of their career to get more championship runs out of their team, à la Duncan or Brady for example. It's not like he needs that stupendous amount of money anyway. AD will be in LA for the long run so letting him walk is not an option, he'll opt-out and then we'll tie him up long-term.They don't have the cap space unless they let AD walk.
Like I said, don't think it'll happen but certainly possible. They didn't sign Giannis' brother to be a key player in this squad, no matter how hard they say they believe in him.