Doncic will be out for Games 1 and 2 at a minimum. Jazz need to try to win both those games. Let's move on and talk about lineups...
Mavs need to start their regular guys -- Brunson / Dinwiddie / Bullock / Finney-Smith / Powell. They need to put their best scorers on the floor, and at the same time they can't put themselves in a position to get completely crushed on the boards. Luka not only leads the Mavs in scoring and assists, he also leads the team in rebounding at 9 rpg. Jazz will have an opportunity to crash the offensive boards. One of Powell or Kleber will need to be on the floor to contend with Gobert/Whiteside. If they really play DFS at the 5, he'll be giving up 6 inches and 40 lbs on our guys. Even if Gobert doesn't punish that matchup, Whiteside will. They might try to buy some minutes with Marquese Chriss in their frontcourt.
With Luka out of the lineup, the Mavs' depth becomes an issue. Off the bench, they have Josh Green, Davis Bertans and Maxi Kleber, which doesn't give them a lot of scoring punch. Those guys average 7ppg, 5ppg and 5ppg, respectively, so they're going to have to try to turn it up a notch. Don't be surprised if Sterling Brown and Frank Ntilikina play some minutes, though neither is an efficient shooter.
DFS is the Mavs' best individual defender, and he'll likely try to defend Mitchell. However, both Mike and Donovan will probably try to bring Dwight Powell into a pick-and-roll with Gobert and get the switch onto Powell who is a mediocre defender away from the rim. The other guy to attack is Brunson, simply because he's 6'1" with a 6'4" wingspan, and guys like Mitchell and Clarkson will just shoot over him. If Bertans is on the floor, then obviously our guys will attack him and make him Peking Duck.
With Luka out of the lineup, the Jazz's main advantage comes from Mitchell and Gobert in the starting lineup, and the Jazz's quality depth off the bench. In this scenario, the Jazz's bench production should really be +15 or better over the Mavs' bench. The Jazz should also have a pretty consistent rebound advantage, if the Jazz keep the Mavs' guards off the boards.