There's no cantilever planned in that retail space.
The drawings show a double height retail space in the drawings on the city site and have been posted in the Apple Store thread - https://urbantoronto.ca/forum/threads/apple-store.4710/page-56#post-1471072
Yeah - that commute to (Tridel I assume?) is a long one from downtown. Have taken the TTC back from meetings there before - not something I'd like to do every day.