Excellent workflow, lux.  Really.  I probably should start using extrude on spline more often.  I tend to get lazy, and avoid drawing splines.  So I would have just extruded the spout with the bevel tool, and adjusted the curvature after the fact, by manually moving vertices or edge loops to bend it into the shape I needed.  I see now that your technique of extruding on the spline is much more elegant, and possibly faster.  I don't think it offers more control, but I can't argue with your result.  It's very close to the original.

Before seeing this tutorial, I would have tried doing the handle by creating a spline like you did, but I would have simply used Loft or Sweep to create the geometry from the spline shape, and bridged both ends to the body.  The only trick to my worflow would be I'd need the exact number of edges on my Loft or Sweep object to make an accurate bridge with the faces on the body of the teapot.  That part requires some thought, and the possibility for something going wrong is higher.  Your technique shown here is probably the easiest, and most fool-proof way to do it.

Great stuff.

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Tools :  3dsmax 2015, Daz Studio 4.6, PoserPro 2012, Blender v2.74

System: Pentium QuadCore i7, under Win 8, GeForce GTX 780 / 2GB GPU.