For the sensor, if you have an original iPad screen, it should include the sensor. If you replaced the screen in the past, by yourself or by a shop, it is possible that it wasn’t transferred over as it requires some soldering. Ideally it should be there but it’s not a big deal, it’s mainly for detecting a smart cover that should turn off the screen when closed.
As for the Home Button, if you transfer over the original button, then it will retain everything. You have to be careful not to damage it while transferring otherwise you will lose Touch ID if you have to put a replacement button in its place.