As you've already figured out, you'll have a great trip no matter where you stay, so stop sweating about making a wrong choice. There really isn't a wrong choice.
Are you staying five nights or four nights? If you are staying five nights, total points redemption makes sense, as the fifth night is free. At four nights, splitting between points and cash makes some sense, although Paris hotels give you the best bang for your points, so I'd reconsider doing all points even at four nights.
I've stayed in a room overlooking the lobby at the CE. It's not horrible, but you are right to want something else. Rooms facing the CE are at a premium, and are noisy, so you probably won't get one nor will you want one. Email them ahead of time letting them know you want a room with a view of the back courtyard and you should be okay. If they give you a room overlooking the lobby, just turn around and ask for a different room. You might have to wait a little bit, but IME, they will accommodate you.
You've obviously read posts from people who talk down the CE as being too touristy, but that appears to be what you want. What many like about the other properties is they are, as you noted, in more residential areas. Last summer, I traveled to Paris with my nieces, who were there for the first time. They LOVED the CE and its location. The street activity, touristy shops, bustling restaurants, etc., were perfect for them. We walked up or down the CE most nights as a last thing before bedtime.
Personally, if I'm going to Paris on points, I'll probably do the SD CY to do it cheaply, because I've done other hotels in Paris already. For a first visit and within your parameters, the CE is a great choice.