Hi Chicagomom. Yes, our DD took the CoGat in third grade. She scored 99% composite; the difference between verbal and nonverbal was small, I don't remember which was higher but they were pretty close.
Her music skills were not as evident when she was as young as your DS, except for generally being a fast learner. At this point she transposes and reads/writes in several clefs, has extremely good relative pitch and a weirdly accurate aural memory. All could be related at least in part to seeing and reproducing/playing with patterns, kind of like learning a foreign language, also something that comes easily to her.
As far as school goes, academics are far too easy, even now with AP and dual enrollment, but she has always been self-motivated to find and create challenge herself, either in or outside of class. Socially there have been bumpy times, particularly in early middle school, but I'm not sure it's anything that unusual.
Hope that helps in some way.
