[obloquy]

It is at least a statement regarding their origins and maker.[...]We know where Dragons came from if not what they were made from or what type of soul they had.

Eru created Goldberry. It doesn't need to be explicitly stated because there's no implication that she was any kind of exception. Eru would not have created Dragons, however, so as exceptions their origin is explained. Still, there is no indication as to what type of being Goldberry was, and likewise for Dragons. I maintain that 'Goldberry = Yavanna' and 'Dragons = Maiar' are comparable issues.

When it comes down to it, it does not explicitly say that Goldberry had a fea, so, following your usual line of reasoning, perhaps she did not.

We can assume she did. She was in 'humanoid' form, and capable of reason and vocalization. There is a big difference between attributing a fea to Goldberry and assigning an unattested origin to the Dragons' spirits. Surely you can see that.

So they would perhaps be bound in life and death to their body.

Right, Balrog deaths appear to be final. I never said they weren't. (Except in the theory I proposed to explain the Battle of the Powers/'3 or 7' note.)

A hybrid with what? It is also said (I believe) that beasts do not have souls. So, what would the Maiar spirit be mingled with? If there was no soul to mix with, then the spirit would of necessity be pure Maiar.

You're right, beasts do not have fear. Consider this, however: The only way Maiar can procreate is by adopting a physical form: two discarnate spirits cannot beget offspring. This means that all offspring of Maiar would necessarily be incarnate, since they would have to be born from a physical mother. They could therefore not be Maiar, as Maiar are in origin incorporeal. Though that does not mean they could not potentially be as powerful as a true Maia, or born with supernatural abilities.

(Oh, and with the Orc thing, you're drawing a parallel more tenuous than any I have made. )

We won't go into it here, but I assure you it is not that far-fetched.

Where does it say that on some level they do not? And for the sake of making a comparison, where does it say that Balrogs do?

On some level they would have (as Maiar).

[...]by practising when embodied procreation they would (cf. Melian) [become] more and more earthbound, unable to return to spirit-state (even demon-form), until released by death (killing), and they would dwindle in force. When released they would, of course, like Sauron, be 'damned': i.e. reduced to impotence, infinitely recessive: still hating but unable more and more to make it effective physically[...]

MT

They didn't completely cease to be, but they were incapable of causing any more trouble. We have to assume that the deaths of both Balrogs and Dragons rendered their fea completely impotent, otherwise they would have simply taken new forms. Nobody seems to fear the possibility that Gothmog, Glorfindel's Bane, Durin's Bane, Glaurung, or Ancalagon will show up again.

By no means am I saying you should change your mind -- I happen to have filled in many of Tolkien's gaps with my own theories -- I just don't think it's fair to represent this particular theory as the most probable.