[Jeff Higgins]

Rick, I sincerely wish you the best of luck with this, but it sounds like you are in denial. You are attempting to separate her behaviors into catagories of "acceptable" (fear) and "unacceptable" (aggression) behavior. What you need to come to grips with is that the former drives the latter. She becomes aggressive out of fear. There is simply no way to placate that in a dog.

Every new thing, every new person will continue to scare her and bring out her aggression. You can try to keep adding to her list of "good" (recognizable, comfortable) things that won't scare her, but it will forever be an itemized list for her. Specific things will populate that list. Similar things don't count for a dog. She cannot conclude "this stranger is good, so most strangers must be good" like we can, or like a "normal" dog can. Fear and aggression have been burned into her psyche as her "default" settings. She has no capacity to ever understand her fears are not warranted. Neither you, nor anyone else, can ever reasure her and explain that to her.

I just hate to see you hang on too long. It just gets harder. With your little kids and their friends about, this is akin to having a loaded gun in the house and accessible to them. The day she bites (or worse...) one of them is the day some one's life may change dramaticaly. Lucy is just not worth that level of risk to one of those kids physical well being (or life?), or your emotional (and possibly financial) future.