Foreshadowing of Leia as Anakin’s daughter

Actually ROTJ is not a light movie. It has happy (but actually bitter-sweet) ending and some light moments but also it has dark moments too. In this movie a lot of people die (I'm not talking about the bad guys, but also Yoda, the Rebel pilots, and so much Ewoks). The optimistic ending makes people forget that but ROTJ is not some "children's movie" as is perceived. Not to mention the role of Leia who is enslaved (like her father) and destroys her enslaver in a "mafia-type" way. So, yes, the raw rage that Leia demonstrates in ROTJ is also a foreshadowing.
Leia also is bold and can be sarcastic as is her father. The moment of the beginning of ROTS/ANH is frequently mentioned: General Grievous, you are shorter than I expected/General Tarkin, I felt your foul stench...etc. of course, this is made deliberately by Lucas to connect the father and the daughter but even as Vader Anakin kept his intelligent, sarcastic wit in the original trilogy.
I would even say that as character, Leia is much more like Anakin than Luke who inherited more of Padme. She is impulsive by heart (while this looks in a way tamed by her manners) she doesn't hide her emotions especially when she is irritated or disappointed but also she demonstrates the positive ones, she quickly can feel anger and rage and she is not patient: at all. Is not a coincidence that she went to liberate Han, without waiting for Luke. It was a bold move but in the end, she failed for her impatience and this impatience is Anakin's trait.