Is there a reason why this can't be 4e for the time being? Considering the book is only in beta, and large amounts of content and plot details are going to be different or changed.. I can't see the benefits of doing the 5e version over 4e, at this point in time.
Maybe when the book officially comes out, but even then.. a few expansion books would be needed imo to really flesh everything out.
Adapting a 4e character to 5e appears much easier on the surface then I give it credit for. Choose high or low stats (or averages) to make the rings, skills transfer over.. etc.