The other 12 incarnations (First Doctor to Eleventh Doctor) of The Doctor have archive audio taken from BBC's archive, instead of new dialogue. The first three Doctor actors have passed away before the show was announced to be in the game, and many actors would/may not sound as good as they were in their time on the show and even some others (like Ninth Doctor actor Christopher Eccleston) might not be interested in reprising their character.
The same applied on The Simpsons characters plus the Ghostbusters and Harry Potter characters as well. It is notable, that the only characters from The Simpsons that speak are voiced by Dan Castellaneta (who voices Homer Simpson among other characters), with the notable exception of the Coyote, voiced by the late Johnny Cash.
The cast from both the Ninjago: Masters of Spinjitzu & Legends of Chima television series did not reprise their roles due to the series' recording in Vancouver, British Colombia, Canada and therefore, the cast for the series characters was done in the United States to prevent Union issues.
Will Ferrell is the only actor from The LEGO Movie to not reprise his role as Lord Business, instead, Ferrell's role was assumed by Nolan North and Liam Neeson is not available during the development of the game. So Archive Audio is used for Bad Cop's dialogue. Melissa Sturm didn't reprise her role as Gail, So she was replaced by Tara Strong.
Thomas F. Wilson didn't reprise his role as Mad Dog Tannen from Back to the Future: Part III, nor any members of the Tannen family likely due to being unavailable during the game's development. Instead, that role is now voiced by Liam O'Brien.
Mary Steenburgen and James Tolkan did not reprise their roles as Clara Clayton and Marshal James Strickland, So they are replaced by Karen Strassman and Christopher Corey Smith.
Hugh Gillin didn't reprise the role of Mayor Hubert due to his death in May 2004. Instead, he was now replaced by William Salyers.
Sean Bean did not reprise Boromir from The Lord of the Rings Trilogy, nor did Christopher Lee as Saruman prior to his Death in June 2015. They are replaced by Nolan North and Roger L. Jackson respectively.
Ian McKellen did not reprise his role as Gandalf, So he was replaced by Tom Kane.
Andy Serkis did not reprise his role as Gollum, So he was replaced by Liam O'Brien.
The characters from The Wizard of Oz have new voice dialogue for the game, likely due to the cast from the 1939 film had passed away even before the game was announced.
Annie Potts did not reprise her role as Janine Melnitz. So she was replaced by Courtenay Taylor.
Rick Moranis didn't reprise his role as Louis Tully, due to his retirement from acting. Instead, the role of Louis Tully is now voiced by Mick Wingert.
John Leeson is not available at this time, So Archive Audio is used for K-9's dialogue.
Daniel Radcliffe, Ralph Fiennes and Helena Bonham Carter are not available at this time. So Archive Audio is used for Harry Potter, Lord Voldemort and Bellatrix Lestrange's dialogue. and Helena Bonham Carter is uncredited at this time.
Michael Gambon is not available to reprise his role as Albus Dumbledore, so he is replaced by Tom Kane.
Tom Cruise and Jon Voight didn't reprise their roles as Ethan Hunt and Jim Phelps. So Archive Audio is used instead, and also was uncredited at Cruise and Voight's request.
Ving Rhames is unavailable to reprise his role as Luther Stickell during the Year 2 development of the game. Instead, the role of Luther Stickell is now voiced by John Eric Bentley.
Jean Reno is also unavailable to reprise his role as Franz Krieger during the Year 2 development of the game. So Archive Audio is used in the level, and is now voiced by the voice director, J.B. Blanc.
Neil Casey is unavailable at the time. So Archive Audio is used for Rowan North's dialogue.
Pat Welsh did not reprise her role as E.T. Due to her death in May 1995, so she is replaced by Audrey Wasilewski.
Mr. T from The A-Team did not reprise his role as B.A. Baracus, Instead that role is now voiced by Dave Fennoy.
Tony Randall is the only actor from Gremlins to not reprise his role as Brain Gremlin, due to his death in May 2004. Instead, He is now replaced by Christopher Swindle.
Dee Bradley Baker did not reprise his role as Brainiac, so Archive Audio is used instead, and he was uncredited like other Archive Audio actors.
David Hasselhoff from Knight Rider did not reprise his role as both Michael and Garthe Knight, Due to Hasselhoff being unavailable at this time during the Year 2 development of the game, instead these roles are now voiced by Nick Offerman.
Michael Cera from The LEGO Batman Movie did not reprise his role as Robin. Due to Cera being unavailable at the time. Instead. the role is now voiced by Robbie Daymond.
Many of the voice actors have worked together in other projects before the game for Year 1:
Chris Pratt, Charlie Day, Alison Brie, Will Arnett, Nick Offerman, and Elizabeth Banks on The LEGO Movie.
Even before that, Pratt and Offerman have worked together on the NBC sitcom Parks and Recreation as Andy Dwyer and Ron Swanson respectively, and Will Arnett had made a guest appearance in the show's second season episode 'The Set-Up' as Chris the creepy radiologist who blind-dated the show's main character Leslie Knope: in real life, Arnett once married the show's lead actress Amy Poehler and had two sons prior to their divorce in 2012.
Joel McHale and Alison Brie have also worked with each other on another NBC sitcom, Community.
Will Arnett and Alison Brie also have starring voice roles in the Netflix-exclusive animated comedy, Bojack Horseman.
Chris Pratt and Alison Brie had also worked on the 2012 romantic comedy film The Five-Year Engagement.
Peter Capaldi, Jenna Coleman, Nicholas Briggs, Michelle Gomez, Julian Bleach, John Barrowman, Neve McIntosh, Dan Starkey and Robert Webb on Doctor Who.
Ellen McLain, Nolan North, J.K. Simmons, and Stephen Merchant on the Portal series.
Troy Baker, Travis Willingham, Laura Bailey, Bumper Robinson, Christopher Corey Smith, Tara Strong, Charlie Schlatter, Nolan North, Steven Blum, Brian Bloom, Scott Menville, Kari Wahlgren, Yuri Lowenthal, and Roger Craig Smith on various DC Comics video games and/or cartoons.
Lowenthal, Menville, Strong, Blum and Cipes had also collaborated in the Ben 10 franchise.
Roger Craig Smith, Liam O' Brien, Yuri Lowenthal, Karen Strassman, Travis Willingham, Laura Bailey and Troy Baker in the Naruto anime franchise.
Bailey, Baker and Willingham also in various FUNiMation anime dubs such as One Piece and Fullmetal Alchemist.
All of these people are also worked together in the Bleach franchise.
In Spain's dub, Claudio Serrano dubs Batman, a work that he has done since Batman Begins. Most of the Batman fans at Spain consider his work their ideal voice for the character.
The following voice actors have worked together before the game for Year 2:
Jeremy Shada, John DiMaggio, Pendleton Ward, Hynden Walch, Dee Bradley Baker, Tom Kenny, Justin Roiland, Ron Perlman, and Niki Yang on Adventure Time.
Tara Strong, Scott Menville, Hynden Walch, Khary Payton, and Greg Cipes on Teen Titans GO!.
Phoebe Cates, Howie Mendel and Frank Welker on Gremlins.
Roger Craig Smith, Karen Strassman, Laura Bailey, Travis Willingham, Liam O' Brien, Mike Pollock, Cindy Robinson, Colleen O'Shaugnessey, Oliver Wyman, Kirk Thornton and formerly Troy Baker on Sonic the Hedgehog.
Colleen O' Shaugnessey, Liam O' Brien and Cindy Robinson on the Viz Media English dub of Sailor Moon.