For the first two I believe the requirements are dominant and top (first one should need dominant trait, second one should need top trait. Just replay his route and make him both dominant and top and you should get both! Especially let him top whenever Haato and him are arguing about who tops, because if I remember correctly the second locked one might be from one of the two times Hikaru asks to be a top). The last locked one is from their visit to Ponpon Land. Didn't you get the Ponpon amusement park event in his route? You get tickets (I think they're given by Fudanshi) and you choose to invite Hikaru.
6 years ago(+1)
I forgot to get this, i think You should give him BJ (lick his d*ck) 3 times or put your di*ck to his mouth to unlock these.
(he must be submissive if i am not wrong)
Still don't found the CG 10th and 15th :'( how do you unlock these