This trade could only work if JJJ and the Grizzlies are unable to get into an agreement with their contract or there is lingering tension still with the style of play that they currently have (especially with their plans with Ja).
The 1st round pick given by Memphis can be a fake one, just to avoid the Stepien rule, Heavily protect it and turn it to 2nds. The 29 and 31 1sts of the warriors are highly valuable, since the trio of Steph, Draymond and Jimmy are for sure retired already, or at the very least they are already in their Vet Minimum Era and are not producing any meaningful basketball.