This is the spoiler I got from 2ch.
Ep7 Haruhi's home visit (Kanazuki appears?)
Ep8 Nekozawa Kirimi (Ouran's chairman/Tamaki's father appears, letters plot included)
Ep9 Host Club's 2nd anniversary party (Tamaki's grandmother appears / Tamaki-Kyoya's first met?)
Ep11 ??? (students' parents will appear in the final scene)
According to someone who has watched Ep7 (from JCOM On-Demand), there's a Black Magic Club scene in the episode, including a certain girl member who is suspected to be Kanazuki Reiko. (the creepy girl that would fall in love with Honey later)
According to a source (seem like he/she got to read the script for Ep8 and 9, probably a filming / TBS staff), Tamaki's father including the letters plot will be included in Ep8, together with the Nekozawa-focused plot.
Seem like Ep9 would be the drama's original story coz I don't remember any 2nd anniversary in the manga. Perhaps it's a story specially made up so they can show flashbacks of Tamaki-Kyoya's first met. In any case, for a live-action, the leading heroine has to show up in every episode, so perhaps that's why they make up this plot. Tamaki's grandma will appear here.
Due to Ep8-9 info she got, the person guessed that the "refreshing / Karuizawa" episode will be in Ep10, but there's no info yet, whether it'll extend to the finale episode, or will it wrap just by one episode.
All we know about the final episode, is that there will be Ouran students' parents on the last scene. (based on the extra recruitment info)
PS: I'll be grateful if the admins can move my spoiler posts in Behind-The-Scenes thread to this thread