This actress is 78, while Sally Kellerman was around 28 when WNMHGB was filmed, so this certainly isn't Dr. Dehner. Even if they did an alternate future where she didn't die, at fifty years in the future she should be wearing a monster maroon like Future Pike was in S1, not a variation on the current uniform. So, no, she's not Dehner nor is she likely to be someone related to her.
)

