In this trade, the Pelicans gain Ja Morant to pair along with what could very likely end up being Cooper Flagg or another top prospect. This would be a great duo to build around even if Zion stays injured. They also gain Vince in order to try and attempt to fill the gap defensively, hoping he can step up in a slightly larger role. Myles Turner is available in the UFA and I'm sure that he'd rather be in the vibrant New Orleans than Indiana of all places.
The Grizzlies gain alot of fallback if their team ends up not turning into the contender they're hoping to make, lots of picks and two solid players plus all the free agency signings can be the start of a young teams push to getting over the hedge. I also believe Dejounte fits the Grizzlies system better whilst also being able to produce a good offensive output along with Herb Jones, who could still improve as a player on offense. All their free agency signings provide required depth, Boucher is a good wing floor spacer who can run multiple positions. Capela is a cheap center that can get blocks and grab boards, which is all they need. Merrill is a cheap end of the bench guy that any team could benefit from having.
Both teams gain, both will likely be in the playoffs. Not enough to win a title but not further away from it either.