You can make it a lot less lose by doing the parts of the job you can do:
- list the pages/templates you need to see reproduce and give a list of them with a url for each
- for each page/template, list the features that are essential and the features that aren't
Even if you want everything, list the templates and for each template list all the features in 2 groups: static/graphic design features and shop/product discoverability features.
Describe very precisely what the dev breakdown will be: where does the work of the WF designer starts and stop, who develop the site, what tehchnology will be used, what are the deliverables.
Describe precisely in what form the graphic design will come to the designer, guidelines, anything. The brief won't be—i hope—"copy this site" so the designers need to know if they have to create a look and feel for you—art direction phase—or if you provide it.
Also you're missing the essential. Start by stating who you are, name and location of the company, what you've done.
So if this is a quote for you to be able to give a quote to your client, that doesn't sound like there is a job behind this yet, that's also something useful to describe, what are the chances this project comes to reality.
All this will, I'm confident, help you to get more serious answers from more experimented designers. Hope this helps!