These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Fanon Discontinuity: Some fans are unsure about the canonicity of the end of both the original manga and School Rumble Z, and not just for shipping reasons either.
Les Yay: Eri and Yakumo make up after the play in the second season with a fast-paced dance that ends up with Yakumo coming out on top in a surprise reversal. The crowd goes wild.◊
Not to mention Itoko being very close with fellow teacher Youko Sasakura.
Yakumo is a frequent victim courtesy of Akira and Sarah.
Akira in general hints heavily towards other girls.
OT3: The Kid's Meal faction (for those just passing by, that's Yakumo/Eri/Harima)