Gap is renovating. Doubt that will be happening.
I'd say we're gonna see a larger store close soon, and then that is where they will put Zara. Of course, it may be placed outside, but I don't think that's happening.
http://www.oxfordproperties.com/leasing/LoImages/rfp/29810_RFP.pdf
The largest stores upstairs other than Zellers, Bay, Sears and Walmart are as follows:
Old Navy 25,941 sq ft (highly doubt it's moving, unless it were to take a pad location)
Gap 20,310 sq ft (not enough space for both a Zara and a Gap in my opinion, unless one of them took space below as well and the mall used the parking lot below as retail as originally planned)
H&M 16,719 sq ft (just renovated, not going anywhere)
Victoria's Secret 11,801 sq ft (units were just assembled, store was just opened; it's not going anywhere)
Harry Rosen 9,987 sq ft (too small for a Zara, don't see it moving either)
Banana Republic 8,548 sq ft (too small for Zara, don't see BR leaving the mall)
Fairweather 8,197 sq ft (again, too small).
I think the only real option is assembling units for Zara or building over the parking lot above Timmy's.
FWIW, someone inquired on Square One's Facebook page about Forever 21 and their response was:
Square One We love Forever 21 and hope to have them at Square One. It’s just a matter of finding the perfect space. Stay tuned . . .