First things first, simplify your idea and concepts. Customers and visitors want a website that loads correctly and gives them an opportunity to access the information that they came there to see.
Web Design is what is known as front end development. Make sure your web designer understands hosting as well.
Will the website be hosted on a linux or windows box?
Will the designer also be handling the use of Cpanel or uploading files or will that be up to the client?
Do you need to register, reserve, secure, or renew any domains? Who is in charge of that?
Where will it be hosted? (We like many web hosts, but there are more that are quite horrible). Brandamos likes HostGator.
Will there be any advanced coding languages involved? Jquery/Javascript, php, perl, python, haskel, ruby, etc? If so will the designer be maintaining that codebase going forward?
What kind of business do you have? Is it the type of business that you want people to call you or send you their information via email instead
Will your website have a map to your business? If it matters, it better be there.
Will the web designer be providing the initial onpage SEO or will you need that from a proper SEO firm?