Huh. Thats kind of a strange shape for a sword quillion.
OK first things first delete the circles they are not needed in this case (yes I know the beziers will be reduced to the thickness of a hair)
Next navigate to the object data tab for the beziers
in the drop down under “Fill” select “Full”
under Geometry up the “bevel depth” untill your bezier looks the way you want it to.
then you probably want a “Bevel Resolution” of 1
back under “Shape” take the resolution slider down from 12 as this will probably be way more high poly than necessary. In this case I will go out on a limb and say that you want 5.
Next once you are satisfied with these settings duplicate your bezier as the next step is unrevokable, and move it to another layer just in case you want to come back to it. Then use ALT+C and select “Mesh from Curve”. Congratulations your bezier is now a mesh object which can have its ends domed and be UV unwrapped.
Can I also do it by converting everything, including the Bezier circles used in shaping the paths, to a mesh, and then delete the now normal ring of edges, and then add in some UV spheres like you said?