2. While Harima loves Tenma, he frequently acts against her best wishes. For example, he ruins her birthday cake for Karasuma which makes Tenma very sad. Occasionally, he does a good deed for Tenma, such as the time he convinces Karasuma to go to her birthday party, but he quickly reverts back to his selfish nature.
3. Anyone in School Rumble, except possibly Tenma, would realize Harima has feelings for Tenma after reading his manga and knowing he wrote it.
4. You make a big assumption in this point, and your statement regarding Harima is simply false. First of all, Harima is not immune to her psychic powers; in fact, Yakumo has read his mind before when Harima mistook Yakumo for Tenma. Yakumo can't read Harima's mind simply because Harima is not attracted to her, not because he's special. Moreover, Harima is not the "only guy in the world" whose mind Yakumo can't read; at Suou's birthday party Yakumo is unable to read the mind of Hanai, a mind she normally has difficulty not reading, because Hanai's mind was filled with thoughts of Suou that day, not Yakumo.
Concerning Yakumo's "mixed feelings" towards Harima, you, and many other readers, are making assumptions. There are no concrete moments in the manga when Yakumo clearly declares her feelings for Harima, and Chapter 205 is no exception; the chapter shows the thoughts from Eri and Harima's perspective, not Yakumo's, so any interpretation regarding Yakumo's actions in the chapter is merely an assumption. Yakumo could have saved Harima because she's a nice person, because Harima is her friend, because she views Harima as a brother figure, or because she loves him. Personally, until Yakumo has a scene like Chapter 85 when Eri clearly realizes she likes Harimal, I'm going to doubt Yakumo views Harima as more than a friend.
5. This is pretty obvious, and has been for over a hundred chapters.
6. Eri did see Yakumo as a rival during the play arc, but stops viewing her as such in Chapter 124 when Yakumo tells Eri she and Harima are not dating. You may be right that Eri still hasn't gotten over her ill sentiment towards Yakumo, though, since Eri is eager to challenge Yakumo in Hagoita in Chapter 161, and she doesn't look too impressed with Yakumo in the most recent chapter.
7. Nothing can seperate two girls' friendship like a man, and there's no reason to believe Eri won't begin to hate Tenma should Eri discover the truth of Harima's feelings. For example, earlier in the manga, the friendship between Eri and Suou is almost ripped apart because Eri believed Suou was dating Harima.
8. Eri's knowledge of Tenma's love for Karasuma isn't connected with Eri being oblivious to Harima's crush on Tenma. Eri doesn't know about Harima's feeling for Tenma because, until Chapter 202, everytime Harima has expressed those feelings for Tenma, Eri has believed they were directed towards her.
9. It's possible Eri does think Yakumo will try anything to get Harima, but Eri doing anything to gain Harima's affection is a new development, and doesn't qualify as evidence from the older chapters. In the older arcs, Eri has backed away when she believed Harima was in a relationship with Tae, Suou, and Yakumo. It's possible Eri will back away again if she discovers the extent of Harima's feelings for Tenma, since, at the moment, Eri thinks Harima just has a great friendship with Tenma.
10. Quite true, and I was disappointed Yakumo didn't simply clear up the misunderstandings in Chapter 205.
Anyways, is this board completely devoid of Eri x Harima fans, or are they all hiding? I know from official and unofficial polls that it's the most popular paring in School Rumble, but everybody at Stop Tazmo seems to be a Riceball fan.