As a goal, that's not too different from the way Stan Lee characterized her. She always was protective of the people she loved; She tried to protect Peter, she tried to protect her father, so it's consistent that she'd try to protect her children. I don't see that as adding anything to her character. And she wasn't honest with Peter. If we didn't have an established history, that would be one thing, but we've already seen her during the time she was supposed to be pregnant and after the children were born and she's acting as though nothing happened.
On Marvels, I agree with your point b. He should have reacted like that. He says they didn't seem to be there to kill people, but still... big invading tank. I really don't see anything creepy about him thinking her behavior is charming, though. He's not seeing her in a romantic way, it's more "I wish I was still that innocent." The thing is, she's acting as though she were an innocent 12-year old, not an innocent 20-year old, never mind that if there's one thing she shouldn't be innocent about, it's the possibility of non-superpowered people ending up as collateral damage when superpowered people are around.