Kellogg was able to speak to the Sole Survivor, using Detective Valentine's body, when all that was left of him was part of his brain. Granted, that was with the help of Dr. Amari and a cybernetic component in Kellogg's brain. Still, if the Institute and Dr. Amari were to work together: They might be able to download the memories and personality off of a dead brain. For that matter, they might be able to download the memories and personality off of a feral ghoul's brain. There may be a cure for Oswald's friends after all!