Director Brian Yuzna on the DVD commentary regrets not coming up with a more proper name for the film as "Return of the Living Dead III" is too long. He suggests the title "Kurt and Julie" and admits that the title "Mortal Zombie" (which it was called in some places in Europe) is a nice name.
According to Brian Yuzna's commentary, Trimark did not require the film to use the same actors or have the same comedic elements as the previous two films but they did require the zombies (including Julie) crave and eat brains.
Penney and Yuzna claim in recent Vestron bluray extras that they felt the need to explain why zombies eat brains. The film explains they need the neurons because their nervous systems shut down. The first Return of the Living Dead explains it by saying "brains make the pain go away". Why a further explanation was needed isn't clear, especially since ROTLD3's zombie seem to eat any body part and don't just go for the brain as in the first 2 films
Brian Yuzna claims (in recent interviews) that the production company put Clarence Epperson up in a motel in Valencia, California while shooting for fear that if they let him remain homeless for that time they may not be able to find him easily for shooting.