To clarify, the issue between the two of us is whether or not Tomomi has a distinct advantage, which I found to be baseless given the four things you mentioned. I certainly believe if she has an advantage it is because of past history and childhood first crush status. Akiharu is more comfortable around her, and does confide in her from time to time. That does not mean he trusts her, nor is the first thought when he thinks of her is that she is a girl, he thinks of her as the dreaded Tomomi, terror of his childhood.

He thought of her as a first love before she began her reign of terror on him. That was eroded under her onslaught until he was terrified of her. To her credit and further evidence, her methods of "torturing" him are a rather convincing sign that she did like him. Little girls that age absolutely pick on the boys they like. The difference is perhaps that Tomomi never recognized that aspect of her terrorism. In fact, I think she has only started to realize it. The closest thing Tomomi has to "friends" are those whom she frequently abuses. Selnia is both her rival and the person she spends the most time with. Akiharu is her only true confidant. She plays pranks on the other main girls, who also seem to trust in her to a reasonable level enough to show parts of themselves they had kept secret before now.

But I don't believe she has a distinct advantage. Tomomi may be the closest to Akiharu, but even if it was out of obligation, Selnia has made the first move. The two are on each others minds quite a bit. Selnia is too dense to realize she likes him, Akiharu doesn't know what to make of it yet, and Tomomi is starting to realize she has pushed him away. I think they are all about equal distance from each other, though Akiharu probably is the furthest along in determining his own feelings, for whomever they may be.