My son is a Norse Pagan, and he is not in the least bit attracted to any of the religions you mentioned either. You can definitely be a solitary Norse pagan...all it takes is to connect with the Gods/Goddesses. After all, it's the deities that make a pagan religion what it truly is.
As far as reconstructionists are concerned, do you really think that if the Norse spirituality had been allowed to continue that they would still be doing things exactly the way they used to? Doubtful. Religions evolve and mature.
My son was called by Thor and instead of looking to other Norse Pagans for guidance, he asked Thor to guide him instead and Thor was happy to oblige. He is extremely happy and content in his religion. It's what religion is really about...not the drama of other humans, but the connection with deity.
Blessings
-Anonymous