The way I'm reading this Mantz and Young, as the only two "Qualified Athletes" (2:08:10 or top 64 on Jan. 30th), are guaranteed spots on the team so long as they're able to hobble across the finish line at trials:
The top three (3) place finishers for both the men and the women at the 2024 U.S. Olympic
Trials – Men’s and Women’s Marathon, February 3, 2024 (the “Selection Event”) will select
themselves via head-to-head competition for a position on the 2024 Olympic Games Team for
the 2024 Olympic Games, provided they are each a Qualified Athlete at the conclusion of the
Selection Event, as defined above...
...In each event, if an athlete declines to participate on the Team or is not a Qualified Athlete at the conclusion of the Selection Event, USATF will offer that position to the next highest placing Qualified Athlete finishing in the Selection Event, continuing in this order until the three positions and an alternate position for each event are filled.
As for the third spot, I interpret this the same as Rojo- if no one besides Mantz and Young breaks 2:08:10 at trials, it will simply go to the highest ranked trials finisher on May 5 regardless of the trials results.
In the case that USATF is not able to select a full team of Qualified Athletes from the Selection Event, or as outlined above in the case that the Selection Event does not occur or ends prematurely , the U.S. may earn up to three (3) quota positions in each gender category. The number of available quota positions will be determined after the Paris 2024 qualification period ends on May 5, 2024. The U.S. will fill any unfilled quota positions with Qualified Athletes based on their rank order on the Road to Paris rank list following the close of the qualification period on May 5, 2024.
Is there good prize money for trials? If I were Mantz or Young I might consider just jogging it and doing Boston or London as they'll probably have weaker than normal fields.