Yes, Smaug was aware of Sauron's return and the growing shadow in the East, and Sauron actively sought an alliance with him, recognizing Smaug's power and potential to disrupt the Free Peoples before the War of the Ring, though their relationship was more about potential mutual benefit than subservience. Smaug, a creature of immense pride and greed, was tempted by Sauron's promises of wealth and dominion but ultimately remained independent, though their interaction in the movies shows a clear understanding, adding depth not fully in the original book.
Why was Sauron afraid of Aragorn potentially possessing the Ring? Gandalf explains it in the Return of the King (during the council after the battle of the Pelennor fields) that Sauron would never think somebody would want to destroy the One Ring.
Near the end of the Watchful Peace, however, Smaug secretly became the ally of Sauron, who had enticed him with promises of wealth and power. As required of their pact, the Dragon would join the Dark Lord in a campaign to conquer Middle-earth.
Certainly not. Smaug was considered “young” when described by Gandalf, so he wouldn't have been around since The First Age when Morgoth created the winged dragons.
Smaug continues his search and claims that he is aware of the Ring in Bilbo's possession and that he sensed that Bilbo has something "made of gold, but far more precious," which in turn forces the Hobbit to remove the Ring.
It's possible that Gollum's prolonged search for the ring allowed it to maintain a significant power over him, suspending his aging process. In contrast, Bilbo's exposure to the ring's influence waned after he willingly (mostly) relinquished it, allowing his aging to resume more noticeably.
Sauron's rise to power in the Second Age is portrayed in the Amazon prequel series The Lord of the Rings: The Rings of Power. He first appears disguised as the non-canonical human character Halbrand, and then in the second season as Annatar (a canonical alias of Sauron), both played by Charlie Vickers.
From what I understand, Smaug is a beast that must eat other living things to sustain himself. For example, he does not "eat" gold and jewels, he simply admires and covets them. It's implied that he ate a good deal of dwarves, men, ponies, etc., during his attack on Erebor.
"The Silmarillion" mentions Morgoth being afraid of everything from Arien (the Sun) and Melian (another Maia), to only coming forth to face the Noldor High King Fingolfin because he was challenged publicly and couldn't refuse without appearing weak and fearing Fingolfin.
At 130 meters, Smaug is longer, but his 110 meter wingspan is smaller than Vhagar's. Vhagar also has a bulkier, more robust body as opposed to Smaug's long and serpentine frame.
His two most salient powers were his knowledge and his voice. Saruman was, in a very real way, the junior brother of Sauron both having been Maia of Aulë, Valar of Smithcraft, in the very beginnings of time.
He will fight in the Last Battle against the Valar and their allies, but will ultimately be slain by Túrin Turambar, the Man he cursed. By finally defeating Morgoth, Túrin will avenge not only himself, but all members of the race of Men.
For the balrog(s)... It's possible, like the drakes, that sauron simply didn't have the same control over them that morgoth did, and that the moria-balrog was awakened by the dwarves entirely by accident.
Elrond chose the fate of the Elves and therefore the choice was presented to his children. The reason why Eldarion and his sisters (the children of Aragorn and Arwen) were born mortal was because Arwen chose mortality and therefore that fate was passed on to the rest of their line.
As a Maia, Gandalf was an angelic being in human form, in service to the Creator (Eru Ilúvatar) and the Creator's 'Secret Fire'. He took on the specific form of an old man as a sign of his humility. His role was to advise but never to attempt to match Sauron's strength.
He did not trust Gollum, for he divined something indomitable in him, which could not be overcome, even by the Shadow of Fear, except by destroying him.
But at the Council of Elrond, Gandalf very specifically says he fought all nine. He drew four of them off when he fled northward at dawn; "This helped, a little, for there were only five, not nine, when your camp was attacked."
Tolkien's description of Gollum conforms to a Catholic – and Thomistic – account of envy, which is a “sadness of the soul”; and it is Gollum's unbearable sadness and his unquenchable desire for the one Ring that marks his character.
Fingolfin, receiving false news, rode alone to Angband and challenged Morgoth to single combat. He wounded Morgoth several times, but grew weary and was killed by the immortal Vala. Fingolfin has inspired artists, musicians and video game designers to create depictions of his deeds.
Dragon sickness, also known as Gold sickness, is a type of sickness that affects Humans, Dwarves, Elves, and Dragons. However, Hobbits such as Bilbo Baggins weren't affected due to their value of home and family.
It is presumed that after the death of Smaug in the Third Age, the great dragons became extinct. According to Gandalf, the fire-drake race survived until at least just before the War of the Ring, and some lesser kin survived even after the war.
Bard the Bowman is a character in J. R. R. Tolkien's The Hobbit. A man of Lake-town and a descendant of the ancient Lords of Dale, Bard manages to kill Smaug the dragon, after which he becomes king of Dale.
Sauron was the most powerful of the Maiar—primordial spirits created to help the Valar first shape the World. His original name was Mairon, which means "the Admirable," and as an immortal spirit born before the world's creation, he was able to perceive the Creator Eru Ilúvatar directly.
He is of the same 'race' as Sauron, Balrogs, and the other Wizards. As for the in-universe explanation, here's a brief history: There exists a supreme being, called Eru. He created divine beings, called the Ainur.
The Elves didn't wear their Rings whilst Sauron has the One. They took them off. They only started using them after the Last Alliance. If Sauron reclaimed the Ring, he'd be able to undo that which the Elves had done with their Rings, and gain control over them.