Ok, after reading over what's been said on this page, and on the older discussion ZET linked to.. I think I finally figured it out. And I apologize for continuing to derail this thread
Simpsons opened up first, and was by itself, a free-standing building. Halifax Shopping Centre opened up across the street with Eatons as its big tenant. At some point the West End Mall was built essentially between the Simpsons building and Mumford Road, and the new mall also featured a new Simpsons-Sears store (later renamed to just Sears, approximately where Winners/Sobeys is today). At some point (I believe kp mentioned ~1983 in the other discussion), Simpsons moved to a new location at the Chebucto Road side of West End Mall, which as Nilan888 mentioned has that awesome parkade under it. However, that wouldn't have been for very long, as Hudsons Bay Company purchased Simpsons around this point, and the new Simpsons store along Chebucto Road would have been renamed to The Bay shortly after.
It is at this point I assume Sears took over the old Simpsons building and expanded into it, specifically the bargain basement with the escalators directly into the Sears store. This makes sense, since I believe the two stores basically backed onto each other.
And finally in 1999 Sears Canada purchased Eatons, and the Sears store in West End Mall moved across the street to the former Eatons location in HSC. And of course shortly afterward, West End Mall saw the major renovations which have turned it into what we see today, and if I'm not mistaken, the Sobeys moved across the street from HSC, correct? I assume it was located at the Bayers Road side of the mall, where that large sporting goods store is today.
So. How's that sound?
One final thing I request confirmation on, and I'll stop beating this dead horse. I assume the Sears store was a multi-level building, as all department stores are - were the ground floor doors located where the Wal-Mart entrance is today?