It could be anyone. It could be Luke rising from the "dead" since that was probably the most criticized thing about Last Jedi. I wouldn't be surprised if Anakin comes back in some form since the Emperor is back. Maybe Anakin will come back to give his grandson a spanking for following the wrong path using his name."The Rise of Skywalker"? So Rei must be Luke's daughter than?
My interpretation is that Luke becomes like Obi-Wan Kenobi and talks with Rei in the spirit form."The Rise of Skywalker"? So Rei must be Luke's daughter than?