Can colleges see that they’ve been listed on a Common App before the app has been submitted?
If you want email from ND, why not just give them your email address: http://admissions.nd.edu/connect/contact-us/
Prior discussions on the topic of non-Catholic admission:
http://talk.collegeconfidential.com/college-admissions/1187640-how-much-does-religion-affect-admissions.html
http://talk.collegeconfidential.com/university-notre-dame/1912162-non-catholic-student-applying-to-university-of-notre-dame.html
http://talk.collegeconfidential.com/boston-college/367073-non-catholic-at-bc.html
There are lots more.