Well got the other posts to how I want them to be...may have bolded a bit too much to highlight points but oh well.
Anyways after looking at Therece's posts and thinking it over I will now answer the two questions to the best of my ability. One, the development of NS and SS, and two how they would develop in various scenarios.
So for the first one lets first look at what we can identify as Sasuke's and Sakura's type.
Let's start with the harder one that doesn't get much focus on this topic. Sasuke when he talked to Sakura chastised her for not training, and when he talked to Kakashi in 693 one of the things that seem to really put him off liking Sakura is her assumption that he already loves her. Now, lets compared that to Karin, who seemed to be the intended love interest of Sasuke before the ending changes. She was chosen to be on Sasuke's team because of her tracking and healing abilities, and he didn't shut down her attempts at flirting like he did with Sakura. My guess is because she was trying to win his love instead of just waiting for it. So going off that, Sasuke's type seems to be 'useful girls that tries to win his love.' While he dislikes, 'useless lazy girls that just wait for him to fall in love with them.'
Sakura I already gone over in other topics and even without that its not that hard to figure out is, 'strong confident and capable boys that compliment her.'
So, like I said before, SS and NS mirrored each other in part one, how Sakura treated Naruto was in turn how she was treated by Sasuke. They both got off on the wrong foot in chapter 3. For NS, the forehead compliment led to Sakura doubling down on her devotion towards Sasuke, if not turning her crush into love. The conversation she had with Sasuke afterwards put him off her by showing him her ugly side, That chapter helped set up their dynamics as a team when they trained and went on missions. Now they had moments and got closer, for the sake of not getting into pedantic semantics. I hope we will all just agree that, Naruto got as close to Sakura as she did to Sasuke during that time.
However, the relationships changed with the Chunin Exam. For SS the curse seal, for NS the pinky fingers and fighting Gaara.
The curse seal turned Sasuke's and Sakura's relationship into a negative abusive one from the second Sasuke got it. Sasuke when he awaken his use of the curse seal, he went on a power hype trip. Where he tried to rip Zaku's arms from his sockets and was going to commit similar acts of cruelty to anyone else he could get his hands on. Sakura terrified and concern at what Sasuke doing begged him to stop. Seeing the terror in Sakura's eyes calmed and shamed Sasuke. But, he had gotten a taste of that power. So, he ordered/pressured Sakura not to tell Naruto, as he would not allow Sasuke to use a power that dangerous. The story makes it very clear that not telling Naruto was a major factor in Sasuke leaving the village. As he would have likely talk/pester him to not use it and he would have complied. Sasuke also shot down any attempt of Sakura telling others. Afterwards Sakura's feelings went from in love with him to constantly worried, fretting over him, fearing he will seek out Orochimaru for power, leaving her, abandoning her, and doubting him in general. Till eventually Sakura had lost so much faith in Sasuke, she finally told Naruto about the curse seal. Though too late to stop him from leaving.
At the start of the chunin exam arc, konohamaru when he saw Naruto and Sakura thought Sakura was Naruto's girlfriend. The way to signal that in Japan is holding a pinky finger as the red string of fate is said to be tied to ones picky. Naruto agreed boastfully and got hit by Sakura for the lie. When Naruto was fighting Gaara to rescue Sakura. When he summoned boss Gamabunta he asked him not to fight in a certain area so to not hit Sakura in any crossfire. Gamabunta asked who is Sakura and his son Gamakichi held up his pinky to say "Sakura was Naruto's girlfriend." This being a simple storyline even Kishimoto is capable of but went over the head of some westerners. The correct way to earn the right to call someone your girlfriend isn't to say it to your friends but to protect her. Afterwards, Sakura went to thank Sasuke for rescuing her. Sasuke immediately shot down the praise and clarified to Sakura that Naruto had saved her on his own and went above and beyond to do it. Sakura then looked at Naruto at an amazed then slowly fond look. In order to show, that her opinion of Naruto had changed. From just a teammate and friend that she cared about to possibly something more.
So, by the end of part one. Sasuke was willing to completely abandoned any bond he has for Sakura for power and did so. Sakura was losing faith in Sasuke and had to seek faith and comfort in Naruto. So by the end of part one SS is at least on the decline if not ended while NS is on the rise.
Sorry something came up I'll try to do the scenarios tomorrow.