I don’t know about the walking distance from GT to SCAD. If it looks too far, it probably is, especially with a backpack and in the event if either hot weather or cold weather. Atlanta has real winters (with snow) and real summers.
Emory operates under the semester system. There’s no inherent conflict between taking coursework under a quarterly system and taking them under a semester system. It may even help because the quarter system finals and midterms will not be in same time frame as the semesterly finals and midterms. Not having them all together will help.
Potentially more problematic is scheduling classes back to back given the commute.