Hm, cryptic as ever Mr. Hull! I will have to ponder this ...
However, the more I've thought about it, the more confident I've become.
At the beginning after the kids join in the fight, the family sits down for dinner. I can't remember the exact conversation, but I believe it's clear that while Bob is proud of the kids, Helen is worried for them. Violet says something like "so we go back to how things were, not allowed to use our powers?" Helen says, basically, yeah, you can't use your powers, it's illegal, which leads to a huge fight with Bob.
After they all join in the final battle with the bad guys together at the end of the movie though, Violet says something to Helen like "you're not mad?" and Helen says "of course not." I think this is the indication of her change -- she has accepted that they can be a family of supers (who use their powers). The final scene has the whole family suiting up to fight some fleeing bank robbers.
If I'm right though, this "it's okay to be supers" change begins pretty early in the movie when Helen agrees to become the face of the new pro-supers movement (though she doesn't appear to accept this about her kids).
Bob is a growth-but-steadfast character. He grows in that he manages to get better at taking care of the kids and being "superdad" but his fundamental outlook doesn't change.
I would not be surprised if this movie has a very similar storyform to the first.
However, I am open to correction!