A notable exception would be Robert Jordan and his Wheel of Time series. He prepared notes so someone could finish the work and his widow picked Brandon Sanderson to finish the series. But I think it feels easier to milk it than to be thoughtful with the life’s work of someone, as this requires a lot “would he have liked it” and to know this you would have to start caring early.
By definition, anonymized data can not be reversed. However, many people do not know that difference. If the data would really be anonymized, it would be fine from a data protection point of view.