Battery, screen and both rear cameras have exact-model guides; camera work can target the wide or ultrawide module.
What to check before buying
Imaging
iFixit's rear-camera guide covers the wide camera, the ultrawide camera or both. One failed lens does not necessarily require replacing every rear camera.
Battery and screen
The screen and battery have different replacement procedures. The Pixel 8a also has its own manual and bill of materials, separate from the standard Pixel 8.