Trivia: The prison guard is played by Mark McClure, who played Jimmy Olsen in the original 1978 Superman movie.
Trivia: The black and red check jacket that Henry Cavill wears when he's talking to Ben Affleck on the farm at the end of the movie is near-identical to the one worn by Clark Kent in the original 1978 Superman movie, when he's telling his mother he has to leave.
Trivia: After a family tragedy, coupled with studio executives' dissatisfaction with the production, Zack Snyder left the film and was replaced by Joss Whedon, who rewrote and re-shot large portions of the movie. After several years of fans demanding an "original" cut, HBO Max funded Zack Snyder's Justice League, restoring the director's original vision for the film, which garnered mostly positive reviews, being largely viewed as an improvement on Whedon's version.
Trivia: In Justice League, Jason Momoa has one line of Icelandic. His pronunciation was so atrocious that when shown in Iceland, which normally subtitles English-language movies, the Icelandic also had to be subtitled...into Icelandic, just so people could understand what he said.
Trivia: In a nod to the prior film adaptations, composer Danny Elfman included several musical cues that included elements of his compositions from the original Tim Burton "Batman" and John William's iconic "Superman" theme.
Trivia: Slade Wilson is played by Joe Manganiello - he also took the role of Flash Thompson in Sam Raimi's Spider-Man trilogy.
Trivia: In the battle against Steppenwolf with the Amazons and the Atlantic people, Green Lantern is visible at least twice. Zeus, father of Diana, is also seen.
Answer: I don't know about the Ben Affleck portion of your question, but when the film was going back for reshoots, Henry Cavill had grown a mustache for his upcoming role in "Mission: Impossible Fallout" which he was contractually obligated to keep. The special effects crew had no choice but to digitally erase his mustache in post-production, which is why his mouth area looks so odd in some scenes (if you have seen the trailer for "Deadpool 2," Deadpool makes reference to this when he notes that the special effects for Cable's metal arm are not finished, and remarks that it's not like they are trying to remove a mustache). Interestingly, a person on YouTube posted a video of them removing Henry Cavill's mustache using a $500 computer, and it looks remarkably better than what this film did with a $300 million budget.