All those contracts total about $28M. If Lebron picks up his option, I think it barely works. I believe the trade rule is 125% + 100,000.
Another scenario would be to keep Gordon and somehow include Anderson. But I have a hard time believing there are ANY teams that would take on Anderson's salary with two years and $42M left. After getting Lebron, they can re-sign (or match for) Capela and keep CP3. They'd have the MLE, but the rest of the roster after that would need to be rookies and vet minimum players. CP, Harden, Capela, Lebron, Anderson and a roster full of scrubs. I don't think that's enough to compete with GS. Nor do I think Harden and Lebron can co-exist. They're both ball dominant players.
I think he has an easier path to the Finals if he stays in the EC with either Boston or Philadelphia. Boston doesn't need Hayward and Irving is already causing some problems with his talk about salary demands. The Celtics still have a ton of picks and they could send Brown, Hayward and picks to Cleveland in a deal (Lebron just exercises his option). Irving can be dealt to a lot of teams.
Philadelphia could sign him outright. And they could go out and find a PG if they're uncertain of Fultz.
LA if Lebron wants to be close to his son and be in the bright lights of the entertainment industry. Could even team up with George and CP3 if they all take a little less and LA trades or stretches Deng. That's a damn good lineup with Kuzma at PF. I guess they still need a decent 5.