The term replicants is used nowhere in Philip K. Dick's writing. The creatures in the source novel are called Androids or Andies. The movie abandoned these terms, fearing they would sound comical spoken on screen. Replicants came from David Webb Peoples' daughter, Risa, who was studying microbiology and biochemistry. She introduced her father to the theory of replication - the process whereby cells are duplicated for cloning purposes.
Deckard's apartment, drawn by set designer Charles William Breen and built on stage at Warner Bros., was inspired by the Frank Lloyd Wright-designed Ennis-Brown House in Los Angeles. Breen actually had plaster casts taken from the textile blocks of the Wright-designed house and used them for the walls in the stage set.