My thoughts on Naru/Saku are that Naruto had a really big crush on her most of his life. It could have turned into love if she had shown the least little bit of romantic feelings for him. I also think part of his feelings for her were tied up with his rivalry with Sasuke. I think a part of him thought it would be an ego boost if he could get Sakura instead of Sasuke getting her. Once she lied to him about being in love with him instead of Sasuke, I think his feelings for her started to change. He saw the futility in it, but sometimes feeling are not so quick to go away, especially when you are on the same team and your lives depend on each other.
He had no females around him growing up, Sakura was always there, sometimes needing to be saved, and other times needing a shoulder to cry on because of Sasuke. She did come to believe in him, respect him and support his goal of becoming hokage. To a confused teen, with no women in his life, he probably felt like she was sending him mixed signals. When you think you have hope, you are not so quick to let something go.
I don't think him letting Minato think there was something going on between him and Sakura was an indication of his feelings for her, I think it was more to impress his father. I think by this time he was starting to let the hope go, if not the feelings, sometimes you always hold a special place in your heart for the first person you cared about.
Now about Hinata, Naruto has had a growing respect for her since Part 1. He did not really know her, and even thought her strange at first. The chunin exams changed that. He saw her determination in her fight with Neji and admired her for it. Her defeat fueled his desire to defeat Neji. He realized then she had the same nindo as him even though he had yet to realize that it was because of him that she had it. During Pain he got to see how brave and fearless she was to attack Pain in order to protect him. During the war he got to see how far she and Neji would go to save his life so that Obito couldn't get him. She got through to him when he was in the depth of despair over Neji's death and Obito was trying to convince him to join his side.
I guess that Kishi will show a lot of flashbacks with the two of them showing how instrumental they were to each other, with at first Naruto being too blind to see it, and then him having been too busy with the war, Madara and Kaguya to even think about it. He will admire her determination to get Hanabi back and start to realize he cares, then when Hinata herself gets kidnapped he'll realize how increasingly important she has become to him.