Hi Fabian, you can use the same Touch Panel / digitiser & LCD. The True Tone function won’t work as older Touch Panels / digitisers (7th Gen & 8th Gen) won’t have. All other functions such as the LCD & Touch work though.
Just transfer your logic board, camera, screen, Taptic engine and speakers so you don’t get any “this part is not original” and you should be good. If you need more help you can join https://discord.gg/abbatg3v and I’ll guide you through all the steps via a video call if you need!
Have you tried to reseat the display cables on your device? First you need to unplug the battery before reseating the cables. If this doesn’t work buy a replacement screen
If the Face ID will not function make sure the cables are correctly seated. If it still doesn’t work then you have a damaged Face ID module and it won’t work again unless you take it to Apple for Out of Warranty Repair. I don’t know about the power button but if thats not seated properly either then it may be a logic board issue. And most of the time you need to use a microscope to see if it is or not.