I am glad to see that Make2D accepts meshes now, but my first try crashed Rhino, so my second try was on a simple shape, and this results in wrongly interpreted hidden edges.
make2d v6 hidden vs visible.3dm (42.7 KB)
I presume this issue is caused by the same wrongly calculated hidden edges for Nurbs, so I would focus on solving this issue before attacking any other features with Make2D.
I can try to make fore examples for you if you need that.