I'm imagining the faces of all the ex-Imperial agents when Luke and Leia are joking around with (they're trying to help him keep his mind off Things) Anakin in the mess hall and Pooja jumps in, calling him Uncle Ani. The Imps really don't know how to react. Hearing Leia call him Daddy once was freaky enough (Bail was Papa to her, Anakin moves from Dad to Daddy, depending on her mood) and sometimes Luke makes these expressions that are a dead ringer for his father's...Now there's a niece too?!
Tbh I can’t imagine Leia calling Anakin “Daddy” myself - it doesn’t seem like either of their styles.
But she definitely calls him Dad. Initially, she called him Dad because Bail was and always will be Papa, but as it turns out Anakin wanted to be a Dad anyway. In the same way, Breha is Mama, and Padme was initially Mother (when all Leia knew of her was her dreams), but as she learns more about her, Padme becomes Mom.
Luke calls Anakin Dad most of the time when other people are around, but when it’s just family he’ll use Ipa or Ena (Amatakka words for father and parent respectively) just as often.
Then there’s Ahsoka wandering around calling him “Skyguy.” And Needa’s daughter Anwen, who calls Anakin by the alternately adorable and terrifying nickname “Mr. Torhu.”
So when Senator Pooja Naberrie shows up and starts calling their resident former Sith Lord “Uncle Ani,” some of the newer defectors are shocked, but most of the older ex-Imps just shrug it off. Apparently the galaxy is full of people who have affectionate nicknames for Darth Vader. It was surreal at first, but you get used to it.