I don't think it's an error... It was written in bold, so I think that's a nickname the students gave him, changing his name.
And it was Dato, not Dota.
Like I said above, all girls know each other and are friends... She would discover it 100%. Way better for him to tell her himself instead of letting her discover later and think why the hell he didn't mention it.
I think it was a smart move... All the girls know each other and are friends, Honoka would discover that they all got presents sooner or later. It was better for him to tell it himself.
The only girl added in the game was Kana, and it's been what, 40+ chapters already... No other girl with romantic interest towards the the MC was introduced yet...