The original home button cable from the damaged screen can be reused with the new replacement screen. If some heat is used, the backlight layers can be taken apart, starting with the metal plate/mirror which has the home button cable enclosed inside. The process will be similar to this:
https://www.youtube.com/watch?v=01ecUhWScBs
'''I highly recommend practicing this on a damaged screen first.''' Depending on what is replaced, the backlight LED power cable will need to be soldered as well.
Best of luck!