I don't think they need to trade Beasley to give max deals to all three...
It's my understanding that a max deal starts at 16.6 mil in the first year. multiply that by three and you have 49.8 mill which I believe they have to spend...
now, if all three take less money per (say a contract that starts at 15 mil per), the three will take up 45 mil and leave 8 mil in cap space + vet mins to add to Beasley and Chalmers.
They also have three second round picks that they are apparently high on in Da'Sean Butler, Dexter Pittman, and Jarvis Varnado. All three most likely could be signed for very reasonable money.
If Wade, Bosh, LBJ all take less money, I'm not sure that they will have too much trouble filling out their roster.