First, I think that Azura and Crystal will play approximately the same number of minutes as each other, regardless of who starts. So, whether Z starts or Crystal starts does not make a huge difference.
Second, though undersized, Gabby and Pheesa did a great job this year and created mismatches with their quickness. If they do get in foul trouble, we have Z and Batouly, as well as Nat, to back them up.
Third, while the other 4 starters can handle the ball well for their positions, no one handles the ball as well as Crystal. She also sees the floor better than anyone, except possibly Gabby.
Fourth, the easiest transition for the team is for players to keep their positions--at which they excelled in a 36-1 season--and replace the missing starter. Thus, plug in Crystal for Saniya.
Fifth, though Z had 2 good years at Duke and apparently has played very well in practice, Crystal has more experience in actual games in Geno's system.
Sixth, when Diana, Maya, Kaleena, and Stewie were freshmen, they were probably the best players on the team, but none of them started, at least until the starters were injured. They basically played starters minutes, but were not starters. Though Z should be very good, I doubt she's better than those four.
I think we start games with a small, quick lineup, then mix in several bench players. As noted, Z will get starter's minutes.