The new Star Wars film has been retooled to centre on the iconic characters of Luke Skywalker, Princess Leia and Han Solo, according to the Hollywood Reporter.

Oscar-winning screenwriter Michael Arndt was replaced by saga stalwart Lawrence Kasdan in October for JJ Abrams's film, which is being pitched as the first in a new trilogy. The Hollywood Reporter's Heat Vision blog now reports that decision was taken because Arndt had planned to focus on the children of the characters played by Mark Hamill, Carrie Fisher and Harrison Ford. Luke, Leia and Han would have appeared in supporting roles.

Kasdan, who wrote 1980's The Empire Strikes Back, will produce a screenplay that centres on the space opera's original stars so audiences can have "one more chance to enjoy them before a fitting send-off", suggests Heat Vision. "The new characters, the offspring, will now be in supporting roles ... and take centre stage in Episode VIII and IX," continues the report.

The dramatic shift might partly explain the speculation that has surrounded casting for Star Wars: Episode VII, the first film to emerge since George Lucas sold all rights to Disney for $4.05bn (£2.46bn) two years ago. "Some characters have disappeared from the Arndt script and new ones are being added," suggests Heat Vision. "For example, one actor who met with Abrams in the fall before the overhaul was Mud breakout star Tye Sheridan. But sources say that at this stage there is no need for such young actors and thus Sheridan will not be involved. In another case, one part that was initially conceived as a 20-year-old male is now being rewritten to be 40 years old."

Nevertheless, those casting rumours keep coming. Heat Vision says Michael Fassbender, Hugo Weaving and Girls star Adam Driver are the latest names to be linked to Episode VII, which is due out next year. Details of the role intended for Weaving are the only ones to have emerged: he will reportedly play an Imperial Commander.

That leak alone, if confirmed, would appear to drop a heavy hint as to the direction of the new trilogy. The presence of Imperial top brass suggests the evil organisation from the classic 1977-1983 trilogy may not have been entirely obliterated with the destruction of the second Death Star, Darth Vader and Emperor Palpatine at the end of 1983's Return of the Jedi.

The Wrap also reports that Breaking Bad's Jesse Plemons could be in line for a role in the new film. The 25-year-old Texan is said to have auditioned for one of the parts that could move centre stage in Episode VII's sequels.

The only character which has been 100% confirmed for Abrams's film is that of R2D2. Disney said in November that the diminutive droid, who appeared in the very first scenes of 1977's Star Wars and has been seen in five subsequent live-action movies, would be returning. Episode VII is currently due in cinemas for Christmas 2015.