Gosh, it's been nearly 2 years since I was last there and I can't actually remember the answers to your questions.
What I do recall is that the hotel is clean and in a convenient location (virtually atop the Shinjuku station). Staff was very kind and the breakfast buffet was fun.
I did sign up for the program but don't recall if it extended any benefits that I would otherwise not have received had I not signed up.
Sorry, wish I could be of more help!