Naruto would probably try to avoid fighting at first. He'd want to understand why Tayuya is after him. He might say something like 'Hey, we don't have to fight! Let's talk this out!'
If talking didn't work, Naruto would defend himself but still try not to seriously harm Tayuya. He believes in the good in people, so he'd hope to eventually convince her to stop. He could use his shadow clones to confuse her and buy time to reason with her.
The story could also take a turn where Tayuya actually has a change of heart before she even tries to attack Naruto. She could learn something about Naruto that makes her realize he's not the enemy she thought he was. For example, she might find out about his difficult past and how he overcame it, and this could make her reluctant to carry out the kill order.
In a fanfic where Naruto is sent to Haven, he might find himself in a very different environment compared to Konoha. He could encounter new types of magic or powers that are unique to Haven. Naruto's strong will and determination would likely lead him to adapt quickly and try to find a way to use his skills to help the people there. Maybe he would form new alliances and friendships with the inhabitants of Haven.
Well, it could be a story where they are in a committed relationship and the 'pregnancy' is more of a metaphorical or accidental magical occurrence that they have to deal with in a very innocent way. For example, they might accidentally ingest some sort of magic potion that gives the false appearance of pregnancy, and then they have to go through a series of comical misunderstandings and adventures to figure out what's going on.
I'm not entirely sure which specific 'naruto futa tayuya fanfic' you are referring to. There could be many different fanfics with that combination in the Naruto universe. Generally, fanfics like these might explore unique relationships between the characters Naruto, Futa (not a typical main Naruto character, might be an OC), and Tayuya. Some might focus on their adventures, or perhaps on how they interact in a different scenario than the original Naruto plot.
A fanfic with Naruto seducing Tayuya could start with Naruto having a mission that involves getting close to Tayuya. He might start by showing genuine interest in her music or her skills as a ninja. As he gets closer, he could use his positive attitude and his ability to see the good in people to break through Tayuya's tough exterior. This could then develop into a relationship that challenges both of their beliefs and allegiances.
They might start with some bickering as they are from different backgrounds. Naruto's positive and energetic nature could contrast with Tayuya's more edgy and tough personality. But gradually, their interactions would become more flirtatious and affectionate as the story progresses.
Tayuya's character can be developed by exploring her family side. Since she's related to Naruto, she could inherit some of the Uzumaki clan's traits like strong will and tenacity. This could be shown when she faces difficult challenges and refuses to give up. Also, her relationship with Naruto could make her more empathetic towards others, as Naruto is known for his big heart.
One big challenge would be not being believed. People in the past might think he's crazy when he talks about future events. Also, he has to be careful not to change too much and disrupt the whole timeline. Another challenge could be that some of the villains in the past might be more powerful than he expected, and he'd have to find a way to defeat them with his current skills and limited knowledge of the past.
Power and self - discovery could also be themes. Futa could be a character who is new to the Naruto world and is trying to discover their own power, and Naruto and Tayuya could play roles in that journey. Also, friendship might be a central theme. Despite their differences, they could form a strong bond that helps them through various challenges.
One popular theme is redemption. Writers often explore the idea of Tayuya finding a new path after her association with Orochimaru. Another theme is friendship. Fanfics might show her forming unexpected friendships with characters from the Leaf Village. Also, power - up themes are common, where Tayuya discovers new abilities or enhances her existing ones.