I used one post for so many episodes because, these episodes all are introducing some character. And these characters, will be important in the near future of the show.
Found this image on http://www.myanimelist.net! Looks cool!
Episode 4’s Title : Hahi! Destroy Girls’ Hearts!
( Hahi! Otomegokoro wa Desutoroi!, はひ！乙女心はデストロイ! )
She’s Haru Miura.
Episode 5’s Title : The Director of the Discipline Committee’s Avoidance of Boredom
( Fūki Iinchō no Taikutsu Shinogi , 風紀委員長の退屈しのぎ )
This mean looking guy is Hibari Kyoya.
Episode 6’s Title : Ni-Hao Gyoza Fist!
( Nī Hao Gyōza Ken! , ニーハオ・ギョーザ拳！)
This “infant” is Ipin.
Episode 7’s Title : The Limit! Passionate Brother!
( Kyokugen! Moeru Oniichan! , 極限！燃えるお兄ちゃん！)
This one with the boxing gloves, is Sasagawa Ryohei.
Episode 8’s Title : The Senior Boss Thinks of his Family
( Senpai Bosu wa Famirī Omoi , 先輩ボスはファミリー思い)
The guy eating is Dino. He’s from the Chiavorone Family. He was Reborn’s ex-student.
Episode 9’s Title : Short Life Skull Disease
( Inochi Mijikashi Dokuro-byō , 命短し ドクロ病 )
This is Dr. Shamal. That mosquito is his form of weapon, a Trident Mosquito.