What Hokage selection. Hashirama, Tobirama had no competition. Third was challenged by Danzou and defeated when he became one. and Uchiha's rebelled in his times and died.
If Fugaku rebelled just because he didn't like Minato being nominated then he could challenge Minato just like Danzou. or wait and see. But starting a civil war over it would ruin the village and his own chances of becoming anything but a mercenary for rest of his life along with his clan. Kushina seemed to be friendly with Sasuke's mom. You are suggesting Sasuke's mom probably didn't return the feeling and resented her position.
Besides Minato was encouraging Obito to become hokage and he had a fair chance if things didn't go south. The very fact that Obito wanted to be a hokage and no one told him he couldn't says it was not that much of a policy. Unless you think Minato was the kind to make one like that. It would be out of character for Minato.
So how it doesn't makes one question the novel?
Hashirama was selected because of Tobirama orchestrating a vote saying others must decide.
Tobirama was promoted by Hashirama and dint get his one by vote.
Tobirama nominated Hiruzen Danzo didn't challenge him for the leadership inside him he coveted it.
Minato was appointed by the 3rd who had fallen out with Orochimaru. And the Uchiha were pissed off because Fugaku had equal achievements in the war but wasn't nominated. Konoha chose to bury Fugaku's and propogate Minato's. The Uchiha saw this as discrimination. Fugaku calmed them down because he didn't want to cause trouble. The Uchiha were stopped from helping in stopping the 9 tails by Konoha's higher ups and forced to help with evac. Fugaku wanted to stop the 9 tails that annoyed the Uchiha because they saw the elders feared they may take control of the 9 tails.
They were even more aggravated once they became isolated and moved into a singular place. Tensions had reached boiling point.
Fugaku didn't hate the village or the people he loved it and tried to avoid the coup until he was left with no choice. That is what the novels address because konoha a village he lord had become unreasonable.
We know konoha wouldn't let the Uchiha just up and leave with their abilities so he did what was necessary.
Also Minato and Fugaku didn't really have issues, neither did he hAve issues with kushina. They weren't the government of the village it was the elders the will of Tobirama senju.
The words of Tobirama in the manga:
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An Uchiha no wonder your with the enemy a very favourable view and opinion of the uchiha if you ask me.
Yet you expect us to believe this same Tobirama trusted the Uchiha and was good and kind to them.
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Again how Tobirama viewed the Uchiha and called it their cursed destiny.
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Tobirama and Orochimaru confirming the isolationist policies of his from the very beginning. Hashirama telling him I told you not to persecure the Uchiha. It's obvious Tobirama started the polices against the Uchiha. And they've been their since his time.
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Tobirama again undermining Hashirama because of the Uchiha.
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Tobirama confirming they'd use democracy but where was it when he was selected or Hiruzen or Minato.
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Here the Uchiha still want to live in the village after Madara tells them to leave even though Tobirama is their enemy.
Tobirama confirms he didn't trust the uchiha in a scan further up and made them into KMP.
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Here Hashirama confirms the village created the problem and not the Uchiha. That Hashirama created it(by lselecting Tobirama).
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Here the 3rd confirming he let Danzo run wild.
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Here Minato confirming the context that the Uchiha coup wasn't just because of the 9 tails. That was more the straw that broke the camels back.
So the mistrust of the Uchiha existed from the beginning it wasn't Obito who made that story up. And Tobirama did those thing he passed them onto Danzo who eventually alongside Hiruzen orchestrated the massacre of the Uchiha. Had the leaf been more trusting and not followed Tobirama's policies this wouldn't have happend.
As for Minato he was trained by Jiraiya who didn't give 2 shits about the will of Tobirama. He was different and Minato was different but Minato wouldn't be able to nominate Obito even if he wanted to since the council (Tobirama's posy) nominates the candidates.
As for Kishi if he confirms the novels are canon he's not dependant on justifying that to you. The novels will only explain the context the manga should be understood in.
Anyway I'm done on this topic.