If the 3D boundary curves are exactly the 3D mapping of the 2D boundary curves in the parametric domain (u, v), then perhaps there is a better way to compute these 2D boundary curves from the given 3D boundary curve. However, very often this is not the case. For a...

First of all, I don't think you need nurbs. Fitting a B-spline curve to your data points should be good enough. If you only have a few dozen points, then it is likely you would like the B-spline curve to exactly pass thru these data points. In this case, you...

You shall read this article, http://www.codeproject.com/Articles/996281/NURBS-crve-made-easy; there are algorithms to convert NURBS to Bezier curve sets written by the author.