Mary, as you may know, there are two different versions of LEED for Retail—one for new construction, and one for commercial interiors.
I haven't yet seen a guidance document telling us which system to use for which retail projects, but I assume it's analagous to the current NC and CI systems, in which case the LEED rating system selection policy should help.
Now, my question back to you is, who is doing the LEED project? If it's the little retail stores, then it seems like they would want to do LEED-Retail-CI. If it's the shopping center owner, it sounds more like a LEED-CS project. Multiple buildings I would register as a block.
I would also think about timeframe and if you want to be a LEED for Retail pioneer. There are benefits to being among the first on anything, but drawbacks, like will USGBC have LEED Online fully set up to support your work when you need it?