At St Olaf you can sign up for The Environmental Conversation program as a freshman, then you can take Science Conversations sophomore year. Only admitted students can apply/sign up.
Faith can be as important as you wish at St Olaf. Chapel is not mandatory, you can attend (there’s no class scheduled during chapel) or you can do whatever you want. They are very big on Interfaith dialogue and have representatives of various faith working on campus and in the Religion department. Your classmates will NOT be exclusively Christian.
Wheaton IL is an evangelical college, more conservative than St Olaf, and where you sign a creed before you enroll (or teach there). As a result, all your professors are evangelical or conservative Christians and virtually all your classmates will be evangelical Christians. Chapel is mandatory.
Academically speaking, especially for science and premed, St Olaf is seen as the stronger choice.