For a consumer web app, I would split it into a Product Designer (someone who can do art, UI design, product concept, workflow, html/css/js), and a developer (who does some js, all server side work, and the related tools.

Finding the product designer is going to be the hard part -- there are a very limited number of visually oriented product designers who can also code. I think that person should either be a cofounder or hired as first employee with 1-5% of equity; on par with a later VP Engineering hire.