Murakami Jun, I think is mainly an actor in movies. I don't watch a lot of JP movies so I'm also not familiar with his work.
Hayashi Kento is one of the better young actors out there, imo, great in dramatic and comedic roles. I subbed his drama Ginnikan, I highly recommend it. It's one of my favorites.
Manaka Ayu is mainly from Takarazawa Revue, where she was a top star. I think she did the female roles.