This trade only happens if Lebron requests a trade and Mavs want him (Based on latest rumors, Mavs were 1 of 4 teams to discuss trading for Lebron James).

The Mavs aren't losing much in this trade; Gafford and PJ play positions that Mavs have depth in, they probably won't extend PJ since they have Flagg, and trading Klay would open more time for other players (e.g. Christie). They also open 2 roster spots.

Hornets need PF and C pieces. Here they get a starting C and a cheaper replacement in Naji for Miles.

Lakers get role players that still fall within the timeline that they want cap space (1 and 2 year deals only).