Not trying to use a sledgehammer to make a point but...
There is also zero chance that Lou or Pheesa come off the bench. Both 1st team AA's, started every game last year in addition to Gabby and Kia. .00001% chance Kia comes off the bench. Heart and soul of the team - leader, intensity, 100% effort 100% of the time. Not an AA, but world class 3 point threat and no one is tougher.
I believe this (above) is the first post even to address the possibility that Kia might not start. I also think it is quite unlikely also (< 5%), but not quite as low as you suggest.
Hypothetically, if Crystal emerges as the Second Coming of Moriah, and Azura proves that she is Stewie Reincarnated, so that Geno and the coaches are forced to conclude that they both have to start, then (IMHO) it is more likely that Kia loses her starting spot than that Lou, Gabby, or Napheesa lose theirs. As you have pointed out, she is the only returning starter who is not an All-American (and it isn't just because she is Canadian). She scored less than the other three, and she was (dare I say it) good but not great defensively.
Her 3-point shooting near the end of the season was indeed impressive, and if that continues, I doubt that Crystal's shooting accuracy will be able to match it. So it would then become a trade-off between Kia's shooting and defense vs. Crystal's speed and passing. If Crystal's defense hasn't improved since last year, it will be no contest. But if Crystal has made major strides in that area and shoots reasonably well from distance (better than last year), then there is a chance that she could get more minutes than Kia.
Even if that happens, I think it will be like the Caroline / Bria situation in Caroline's senior year. Caroline started (out of respect to a senior who gave the program everything she had), but Bria came in at the first time-out and got the great majority of minutes for the rest of the game (if it was competitive). It is quite improbable that Kia would actually be pushed out of the starting lineup.
But really, I think the overwhelming probability is that the four returning starters continue to start, and either Crystal or Azura comes off the bench. If Crystal is the normal starter, then I can imagine that Geno might replace Kia with Azura in the starting lineup if the other team had a major weapon in the paint -- someone like Kalani Brown or A'ja Wilson. That would be a first for him (to my recollection), but it is not inconceivable.
ALSO: Someone above said that only Geno and the coaches know who is going to start. I disagree -- I don't think they know either at this point. I think they will all bend over backwards to keep an open mind, so that the final decision is based 100% on what happens in the next month, as opposed to anything that happened last year or on other teams. That is as it should be.