@pac12bound My daughter picked CS on her application and entered as a CS major. However, I believe becoming a CS major is simply a matter of declaring it - unlike majors such as business with a separate school and application process (e.g., Kenan-Flagler).
However, if he wants to do the BS/MS program he’d apply in his junior year - there’s info on the CS Department web site on requirements. The BS requires more math compared to the BA option. With the projected shortage of computer engineers I think the BA option is perfectly fine.
Also, I don’t get the sense from my daughter that the CS program is cut throat. The CS professors do things like make “test programs” available to student to help them check their projects. My daughter is still in her first year but she already tutors her classmates for some extra pocket money. (Some of the introductory CS classes are a popular way for non-CS majors to fulfill a gen ed requirement.)
I’d agree that with a differential of only $3K per year it’s reasonable to choose either UNC or UCLA. Both are great schools so he’s in a good place.