Father: Shikaku. Reason- I like the way he handled Shikamaru's grief after Asuma was murdered by Hidan. He's also there for his child and intelligent. Out of the Naruto characters, he's the only father figure I really liked. The rest were pretty bad imo tbh, irresponsible/abusive/ignorant/non-present fathers seem to be a thing in this manga. He also remained calm and comforted Shikamaru as a meteor sent by Madara was hurling towards the intelligence base he was in charge of. Calm and collected. Ha.
Brother: Itachi. Reason- I don't think an explanation is needed. But I like to ramble on so I'll give one anyway.

Yes, for the sake of plot and due to circumstance, he was a questionable brother (ayeee revenge quest so my little bro can direct all of his anguish at me instead of himself) but when you keep in mind all that he did and his mental strength, well this is likely why many fans love him. He's one of the more unique brothers in anime and would have been one of the best to Sasuke had he not been a victim of circumstance when he was young. He also had a pretty normal sibling relationship with his older cousin Shisui and I really liked this bond (what little we saw from the manga and the large amount of description in the novels). I like his interactions because they are more realistic than the interactions other characters have with their "brotherly figures" (EX: Kakashi/Gai- too exaggerated and boisterous, Naruto/Sasuke- too violent/competitive, Ay/Bee- Ay said he wouldn't mind killing Bee if it stopped Akatsuki from getting their plan finished, Kin/Gin-only mutally healthy bro relationship in manga but they're both insane so..., Indra/Ashura- They tried to kill each other for years, and it goes on). Keeping in mind that this would be real life, well this would be perfect. Because Itachi wouldn't need to decide my path for my safety or anything, we could just be siblings and not worry about political matters, ninja matters, etc. We could both be at peace with it all. No facades or anything. Just ourselves.
Son: Mitsuki. Reason- I like his chill personality. He has Orochimaru for both a mom and dad and isn't worried about it. I could be a better parent than someone like Orochimaru. I'm sure nearly everyone on this site could. So, it seems like this kid doesn't have very high standards. He also looks pretty cool and I like his blunt way of speaking. His abilities are reminiscent of Luffy too, which is a character from another series I'm quite fond of. Yeah, this could work out.
Daughter: Ha. None of them.
Boyfriend: Ha. None of them.