Trivia: Shortly after the battle begins, Bard rides to Dale to look for his children. A woman tells him she saw them in the old marketplace. When he starts to go there, a man comes running and shouts 'the Orcs have taken Stone Street'. That is an in-joke: Stone Street is the name of Peter Jackson's film studio.
Trivia: Fans may be unaware that Billy Boyd, who played Pippin in the Lord of the Rings movies, sings the end-credit song, "The Last Goodbye."
Trivia: This film has both the final acting role for Ian Holm, who played the older Bilbo, and the final live-action role for Christopher Lee, who played Saruman. (His only roles after were voice-overs.) Holm passed away in 2020, while Lee passed away in 2015.
Answer: Aragon is 87 in LOTR: Two Towers (as mentioned in the extended edition). The Hobbit takes place about 60 years before that so Aragon is 27 at the time. Sauron is banished to Mordor in Battle of the 5 Armies. You see his "spirit" flee and the White Council, mention he went back to the east. Between Sauron and Sarumon, it's mentioned more in other LOTR books, but Sarumon (while still technically good) has been looking for the One Ring. He does not join Sauron as much as uses the alliance for his benefit hoping to find the ring first.