From JShoujo Scans:

1-3) Koutei Gentei
Mio and Ao are twins and they resemble each other in almost everything, beside the fact that Mio is a girl and Ao is a boy. They get along quite well and they always support each other, so when Ao tells Mio that he wants to become a member of LUNA, a group of young models, she is very excited. But unfortunately Ao can't attend the casting so Mio cuts her hair and decides to impersonate her brother for the casting. Though at the casting they immediately realize that "Ao" is actually a girl, they decide to let her...

4. Ijiwaru na Hitomi ni Kisu wo Shite
   Akane and Akari are twins but they couldn't be more different. While Akane is a model, Akari is just a plain high-school girl. When Akari goes to her sister's work to deliver something she accidentally runs into Gaku, a very popular model, but had no idea who he is? Akane enlightens her, and soon after Gaku takes Akari on a date...

5. XXX My Little Honey
   Riko first met Joseph on a photo shoot when she was eight and fell in love with him. Seven years have passed but he doesn't see her as anything more than a little sister, much to Riko's annoyance. Can she get the older Joseph to see her as a woman?