The cover for "Fifty Shades Freed" is the exact opposite of "Fifty Shades of Grey". For the first movie cover Anastasia is the one with her arms up while Christian is the one about to kiss her, for this movie cover Christian is the one with his arms up while Anastasia is about to kiss him.
The trivia items below may give away important plot points.
At the end of the movie it is shown that Anastasia and Christian have a son and that she is pregnant again. Although is not shown in the movie, their son's name is Theodore Raymond Grey and the baby she is carrying it is girl, planned to be named Phoebe. It actually is shown after a few credits are played.
A nod to Bella's Meadow in the 'Twilight' series can be seen when Christian goes to visit his birth mother in the graveyard at the end of the movie. The description of the flowers in 'Twilight' match imthe ones found in the cemetery.
In the book, Kate's brother, Ethan, accompanies the group to Aspen and is pursued by Christian's sister, Mia. He does not appear in the movie and his role was incorporated into Jose's character. However there is no romantic interaction with Mia.