It's often said it's so hard to replace the battery on the Pixel series that's because they have thin vesels and super duper fragile.
To prevent this problem, we have to heat the display properly and using picks applied little amount of IPA and pry it over with them not to touch the LC part. After that you can put older display and replace it. It does take so much effort.
With transfering the assembly, called "Induction", which is placing on the top of the display, from your used iPad, Face ID and True Tone will work properly WITHOUT reprogramming them, that's because True Tone of the iPad isn't paired to them, not as iPhone's.