Be aware that nowadays marketing requires a lot of data analysis or statistics coursework to be worth it (they won’t require it but marketing majors earn much less if they don’t take those classes. ) that being said, with A Level maths, you can start in calc based statistics without a problem (NOT “elementary stats” which is typically a “light” class for kids who have not taken calculus).
If the standard UK to US conversion is used then yes you have a good shot at Honors college but of course it’s more competitive than "just"admission.
Show the “standard conversion scale” to your GC to know whether that’s the one they use in their school profile&documents.