I agree with pony about doing it in post. If you do it in the render you are stuck with it (barring a re-render). Where as if you just render the light or a sphere or something to represent the light and then blur the hell out of it and make it brighter in comp (which is what a blur essetially is!) then you can tweak and control it without re-rendering.
As for duplicating the lights and keeping the glow you would need to turn on "Duplicate input connections" in the duplicate options. But I think this would mean they all had the same glow attached to them. Try it.
And if that fails, why not do one and write down exactly what you did and then follow your instructions for the rest of the lights? You can even open the hypergraph and look at the connections it makes for the one light that does work and then copy the connections on the unconnected nodes...
Technical Director - Framestore
Currently working on: Your Highness