Sorry to say, but the best thing for you, your husband and your children is to distance yourself from your parents and sister. I'm saying that not as a figure of speech, I mean a LITERAL distance (cross country AT LEAST). Your sister has a NEED to have access to you, your husband and your children in order to manipulate you and interfere in your lives (she doesn't really have a life and mind of her own, she lives THROUGH you). She will cause strife between you and your husband and daughter if at all possible. Most of all, your sister likes to cause sadness so she can have power, but she will, at times, let her victims feel happiness (like "Aren't you glad I gave you that penny for your birthday?"...I'm such a good person,...unless you're an ingrate), in this way she will also CAUSE happiness (CONTROL). She wants to "CAUSE" [everything and anything] because she is a control freak, and because she NEEDS the glory for her injured conscience.
Yes, you're in a bad situation,...and it's going to get worse. I'm 53, I come from a dysfunctional family and was always ostrascized as the most principled, noble, gentle and level-headed of the children. Psychologically, my mother and sister resented me because I was principled, gentle and noble. Your lack of insecurities does not validate them (does not flatter them). Your attention to absolutes (truth is truth is truth, etc.) represents a challenge to them, that is why you will always be considered an outsider and a target for their frustrations. They can't match your attention to absolutes, so they want to CONQUER you.
The "team" (mother and sister, mother and husband) validates each other. Explain this to your husband that they will cause strife and gently and carefully explain to your daughter that your mother, father, and sister have different lifestyles and do not have your daughter's best interests at heart (since they spoiled your sister, they have bad judgement and will spoil your daughter), but also teach your daughter that your ways of health and rational thinking are good so she doesn't fall prey to your sister's "fast talk". Teach your daughter to be wise and careful not to do things because your sister says they are safe. Teach your daughter not to think like your sister. Your sister will be irresponsible around your daughter and encourage your daughter to be irresponsible, careless, and disrespectful of other people and their property.
It is a sorry situation, but it is still early in life enough to prepare your family to guard against it.
I'm sorry that you have such a situation to deal with, but understanding this early will help you protect yourself and your family. Your sister might get (or already be) involved in some illegitimate schemes such as identity theft, con games, etc., be careful of your personal information. She might forge your signature and use your social security number and you won't know about it until months later because people like that believe they have the right to do whatever they decide they should.