Tolkien wrote about 'evil' beings and their allegiance to Sauron. As part of Morgoth's force, creatures like orcs, trolls, and dragons could refuse Sauron's command and still maintain allegiance to their original 'commander' Morgoth. This does not mean they would, necessarily, since we see loads of orcs on Sauron's side.
Smaug could've been used by Sauron. Durin's Bane would've been a more difficult situation, but as greedy as Smaug was, I don't think he would've required much persuasion to join Sauron's army.
As for the Ring not fitting Smaug's finger - why wouldn't it? Surely you don't think that Sauron, Isildur, Gollum, Bilbo, Frodo, and Sam all wore the same ring size!
__________________
...take counsel with thyself, and remember who and what thou art.
|