Battery, screen and back glass have separate guides, but display replacement can involve Apple's part calibration or pairing steps.
What to check before buying
Display
iFixit notes software-related finishing after screen replacement on supported iOS versions. The physical screen job also needs new adhesive.
Battery and rear glass
The battery and rear glass have separate procedures. The rear-glass guide calls for fresh adhesive, so a cracked back panel is a distinct job from a worn cell.