Do you love coding? if not, you should leave it up to the supplier to ensure the webshop fulfills your business's needs
Why dont you break up the project into stages? and work your way up?
If you choose the right developer/provider, they will ask you all about whats needed to make your business work, rather than talking about which theme or plugin should be used
Because your job as a business owner is to focus on what brings in the money right?
Why code, or look at plugins and such, if you dont earn your income from that?