-So basically the snake ran a long, long gambit to continue to exist forever by engineering events that would lead to the creation of the endless world (the heat haze daze) and a new Queen, who would continually reset the world forever so that she can continue to spend time with her friends.
-By doing this, the snake can continue to exist through Kenjirou's wish endlessly, as it would never be fulfilled because only a complete Queen has the power to make his wish to see Ayaka again possible, and the Queen cannot be completed due to Ayano's actions.
-The creation of the daze and the deaths of those who were swallowed by the daze were all recreated by Marry in every timeline, as those were the circumstances that led to Marry meeting her friends in the original timeline. This is why the same people die and receive the snakes in every timeline.
-The incomplete Queen Marry created a new snake from her feelings of wanting to relive the past, bestowing the power on Shintaro. From every timeline after that that, Shintaro has the Retaining/Recording/Branding Eyes/Reading Steiner, which allows him imprint and recall all of his memories, even from previous worlds.
-Shintaro is thus able to reach the endless world, retrieve Ayano, inform her of her power to convey her thoughts (the Favoring Eyes), and lead her to berserk Marry.
-With Ayano present, Marry becomes the complete Queen. Ayano uses her ability to convey Shintaro's memories of the previous timelines to Marry, who is able to gain control of her Queen powers and commands the endless world to swallow up the entire world.
-With that, Kenjirou is reunited with Ayaka and his wish on the snake is fulfilled, forcing it to seek another wish in desperation to continue existing.
-The snake is unwillingly made to grant Konoha's final wish to save Hiyori, and is turned into a surrogate life for her, allowing her to return to life. With the wish fulfilled, the snake goes silent, its consciousness ceasing to exist.
-Marry divides the snakes once again and returns them to her friends, including Haruka, allowing them all to exit the daze as she creates a new future.
-Konoha is a separate existence from Haruka. The Awakening Eyes and the Opening Eyes are part of a set: the Awakening Eyes creates a new body, and the Opening Eyes allows mental transfer to the new vessel. Konoha's "persona" is just his snake acting on its instincts to fulfill its master's last wish.
-Ayano had always been able to leave the daze, but she was unaware of what was going on outside of it, and remained inside believing that she had to in order to prevent her siblings from being killed by the completion of the new Medusa.
-The Ayano speaking to Shintaro in his dreams is actually his snake taking on Ayano's form, attempting to awaken his memories of its existence.
-The "you need two people to enter the daze, and you need a sacrifice to leave it" theory is debunked. It's shown that Takane and Haruka both entered the daze individually and each escaped with a snake inside them without having to sacrifice anyone (although Haruka's soul ended up being left behind.) The only hard rules here are that it will pull in people who die on August 15, and if multiple people end up in the daze at the same time, only one can receive a snake and escape the daze. Shintaro entered the daze by committing suicide, was restored to life by the snake that had resided in him since the previous timelines, and was thus able to leave the daze with Ayano.