The profession of interior designer requires more than creativity. A successful career in the field requires formal education as well as training and discipline. The reason a college degree is needed for such a profession, is that it is not only bounded to the selection of styles and colors, but they need to have a complete knowledge of building codes and inspection regulations in order to achieve and comply with the state laws.
Apart from the interior designer and for large scale projects, an Architect would be the best solution for your needs, once such professional is trained in design theory, engineering, and project management. Architects are skilled at coming up with inventive ideas to solve compex design problems and at making sure a project is true to itself aesthetically.
Either or you choose, just make sure to ask for their certification, to ensure not only that indeed you are hiring a professional, but to not get locked in financial troubles when hit with fees for not having a licensed person to do your project.
