Can he meet with the GC and see if he can get his desired Econ class without losing too many of the teachers he likes? I don’t know about your school but we only have 1 or 2 AP level teachers in each subject so re-arranging the schedule isn’t likely to change too many of the teachers.
I don’t see why 2 English classes would be perceived negatively–plenty of kids take 2 science classes or 2 math classes. My kid takes both English and writing so if you consider writing to be English, she will graduate with 8 English credits. But AP Econ probably looks more impressing than English mythology and if it’s what he wanted, I would try to get that to work.