It is too soon for you to be asking Embry-Riddle vs. U of ND vs. Fill-in-University-Name-Here. The time to ask that question is after you have been accepted and you have determined that the places all are affordable.
You seem to be an international applicant. If that is true, you need to very carefully verify E-R’s information about work as a student assitant flight instructor. In the programs I am aware of, those jobs only can go to US citizens and legal permanent residents because of restrictions on work permission for international students.
Yes, the weather in Grand Forks can be challenging. I used to live there and I knew a lot of students who were in the flight school. They loved their program and learned to cope with the winter.