Considering that the creature in Harry's chest is a metaphor for his jealous attraction to Ginny Weasley, perhaps it is not best used in this context.
Regardless of "whether."
"His immediate friends, those he trusted implicitly and knew could leave without looking back, he had evacuated soon after he made his decision. "
This sentence doesn't quite make sense. Try breaking it up into smaller ones. I think it means that Ron and Hermie moved to the U.S. too, but I don't think either'd have left the fam behind.
Hmm. This would have been funnier if Harry had been perfectly happy being Jerry and had either had zero interest in the rest or a smirking attitude of "See, those whiny losers really didn't need me."
All in all, though, this is a nice little 'fic.