I think if LeBron goes to the Cavs, it's more likely he wants Carmelo than Love, for a few reasons.
1. The Cavs would likely have to give up less talent in a sign and trade for Melo. Melo can straight out walk from the Knicks - the Cavs might be able to get him without giving up Wiggins by offering a couple decent vet players instead. In any Love deal they would absolutely have to give up Wiggins.
2. It would allow James and Melo to float around in positions on the court. They could each play some SF, PF and in LeBron's case some off guard - more versatility.
If Lebron to Cavs
Then Love to Boston, Carmelo to Cavs.