I'm no translator, but I can give you the gist of what I
believe they're all saying.
Risa says Aichan is stubborn and has to have her way. When she has her mind set on something, she'll definitely go after it.
Eri says Aichan is kind, modest, humble, always gives her best at rehearsals and greeting others. Eri thinks that part of her that never changes is wonderful.
Sayu says she admires Aichan. Since before Sayu joined, her favorite member was Aichan. When Sayu entered, that didn't change. She really admires how Aichan sings, dances, etc
Reina says Aichan wears old-looking clothing.
Aichan on the couch:
She really doesn't know what to say so she gives a question.
"This year, how old will I turn?"
"The answer is, I'll be 23."
She still doesn't know what to say.
Koharu says she is a really good person who values the group and makes sure each member knows what she has to do. Koharu is glad she's the leader.
Aika says Aichan's singing is passionate, and she loves her dancing, which she describes as "sexy-cool".
Junjun says Aichan's reminds her of a mom. (In another section, she described Risa as like a dad in that she's reliable.)
Linlin says Aichan is a charismatic leader. When she sings and dances on stage, she has a sexy gaze that makes even girls' hearts jump.
Next section on the couch:
"Do you like my hair long?"
Some stuff about her mom liking it.
She talks kind of fast here so I didn't really catch all of it.
Edit:She asks the people watching do you prefer her hair long or short. It doesn't really matter to her. Some people have said that they like her short hair, but there are also people who like her long hair better. In other news, her mom prefers the short hair. In the end, she can't decide. Typical Ai-chan.
Aichan says she is the biggest mystery to herself. She really can't figure out how to describe herself in one word.
"Cat... I don't know! Not really a cat."
"Country bumpkin? No that's not right either."
She eventually settles on "crybaby".
Last couch section:
Some chat with Reina at the end, about what food she's into recently. Aichan says "Honey-pickled plums" from Osaka, which Reina bought 4 jars of.
Talking about what they're wearing, kind of a "rock feeling". Aichan's outfit reminds Reina of Pink Lady.
Aichan tells Reina she asked the camera how old she would turn this year. "They'd definitely know that!" Reina asks the same question, with the hint "I'll become an adult."
Reina remarks that as of next January, she will have been in Morning Musume for 7 years. Aichan is amazed.
Reina reminds her that she and Risa have been in the group the longest. 8 years going on 9 in August.