Exactly that mans role is likely going to expand even if all he says is...."oh so he must be the lucky one, I can see why Sakura"
As for the Kakashi and Iruka thats just ppl being annoying and same goes for Naruto and sasuke their just friends and both are just emo.
I cant fathom how someone could support sasuke and sakura...sasuke is EVIL, tried to KILL her, and NARUTO, abandoned the village, Im sorry I just dont get it.
You would think everyone would pull for the underdog (Naruto) I mean that is the essence of this manga/anime.
I think the Love Letter Ninja Dude saying something along those lines while in the presence of Naruto and Sakura could be possible. Maybe Naruto would find the love letter which would lead to a misunderstanding which could either lead to a fair amount of humor or drama. Hell, maybe the Love Letter Ninja Dude somehow knows who Naruto's father is (Alliance intel on KB and Naruto or something like that) and would state a fist fight with him due to Minato killing one of his friends in battle (whether he's a Stone Ninja or from another village I can't tell without the headbands because I don't automatically pay attention to village uniform and clothing) or something along those lines.
Those are just my thoughts.