Gonna be honest, I only watched for ForceBook and SantaPerth. When it came to the third arc, I skipped until they showed up. I have never heard of the other actors.
Seven Days: Monday-Thursday, Seven Days: Friday-Sunday, Takumi-kun Series 1-5, and Love Place: Shiwase no Katachi. You can find these on YouTube and Dailymotion and kisskh (just beware the quality isn’t great)
I’ve watched this series 3 times and I can praise it for what it is, it’s shot beautiful, there is great story and character writing but the one thing that will never sit right with me other than Eiji’s age is the threesome.