Trayvon Martin does not fit definition #1. Even if we take everything you posted at face value, all we see is a kid who skipped school, denied being a hoodlum, and called himself 'gangsta'. The allegation he had burglary tools and jewelry was never substantiated and the newspaper that carried it pulled the story. But let's act like it was a substantiated claim and that Trayvon had a screwdriver and jewelry of unknown provenance in his backpack.
What you are missing is that it appears that he reacted to being followed by jumping the guy. That, coupled with his apparent criminal record is what is getting him labeled a thug.