Icon to me means a relevant figure in popular culture whose presence is distinct. Legend however means someone who has firmly established his or her place in the music industry as far as honour, notability, and prestige throughout a course of several years (15, maybe even a generation of 25 years) and who surely will be remembered in the next generation, not just the era in which they're successful.
Britney Spears, Lady Gaga and Adele are icons.
Madonna, Mariah Carey and Aretha Franklin are legends.
Legend is the graduated state of an icon and because of that, no definition for Halsey exists.
Halsey has surpassed those aforementioned statuses. Talent - not everyone has it
