Well, to be honest "I think my feet are to big for girl" is lesser sign of insecurity than "My crush wants other one, let's hook up with first one coming". I am not bashing her. People do mistakes, like you said. But my point is this mistake was fruit of insecurity.
Again, I am not trying to change your preferences, I am just saying, from my understanding Lana is insecure. She hides under the image of no nonsense tough girl, but it shows. As for Heather... well, I think I said everything. (And I actually like her that way).. Besides, at every character at any game, novel, movie... we can find pros and cons... also, sometimes negative traits make character better...