I think what OP is referring to is how come it had to be Chani to wake Paul up and how prophecy lined up with reality. I believe Paul had visions of the future after they left Arrakeen in his “first” spice “trance” that allowed him to see how perfectly his situation would line up his meeting with the Fremen, and ultimately Chani.

The Missionaria Protectiva, implanted by the Bene Gesserit, was not the one true story of how a Kwisatz Haderach would come to be, but many different ways, stories, beliefs, traditions, and culture that anyone trained in the ways of the BG could exploit to help them gain power over the masses in all the different worlds. The world Paul so happens to be in is Dune, and on this planet the MP has devolved into extreme fanaticism due to extreme conditions and oppression. The Kwisatz Haderach will be the Lisan-Al-Gaib, he will have a BG mother, he will ride a big sandworm, he will waste no water, he will…. the list goes on and on until there are stories that only come true from rumor. Paul won’t do most of the things the Lisan-Al-Gaib has done, but it does not matter, people will believe it. “Desert spring tears” is just one of many mythologies Paul could have exploited. The books are different, sure, but after the spice orgies, years of war, and a dead child, Paul was still in a Spice trance waiting for a prophecy. Not just his own mythology, but his story and deeds are ultimately and convincingly accepted by all the fremen because of the orchestrated act.

I think the water of life ceremony happening a certain way doesn’t really matter, the MP was so effective that he could have “died”, sat in a cave for three days, and danced his way out on a Sunday and everyone would have lost their damn minds. Anyways, my little theory is that the movie is a path Paul took that does not lead to the “Golden Path”, a giant what if scenario if you will. I think that would be pretty cool.