Situational Irony: Emperor Palpatine
Emperor Palpatine, who fell down a mine shaft (something which should have killed him), survived and remained hidden for years.
Situational Irony: Chewbacca
Chewbacca, a staple of the Star Wars series and a character who is beloved, is thought to suddenly and violently die by the hands of the First Order. In fact, he survives to the end of the movie.
Dramatic Irony: Lando
Audiences (perhaps clued in by the film's trailer footage) know that the mysterious man in the crowd is Lando before the characters in the film know that the character is, in fact, Lando.
Dramatic Irony: Leia's Death
Audiences know that Leia has died before other characters in the film - mainly Rose - know that she has died.
Verbal Irony: C3PO
After C3PO tells Poe Dameron that he can't translate the Sith language, Poe says that "So you're telling us the one time we need you to talk, you can't?" This is sarcastic and ironic: C3PO often talks incessantly, something which Poe is making fun of.