Even if the goal/role is to be the non tech founder, it's important to learn the basis of html, CSS and Javascript. It will give you another perspective when you think about how to implement an idea.
We brought on a third (largely my doing), as more of the operations / finance side. Didn't set roles, and my biggest gaff of all was to not make him vest.
After a year, the third founder turned into a maniacal control freak and almost sank us. Finally departed, but took his equity with him.
My biggest lesson so far is be very careful who you partner with and ALWAYS vest. Or another way to put it, you don't need to worry about the good times, it's the bad times you need to consider and pre-negotiating the divorce is critical.