Yes I know that for a fact I have 4 sisters and I have tried to sneak for something and they always get you in trouble.
Yes
Legally, your sister cannot keep you from accessing your personal items in your parents' house. As a co-heir, you are entitled to your share of the inheritance as determined by your parents' will or the intestacy laws of your state. If your sister is acting inappropriately, you may need to seek legal advice to enforce your rights.
Yes but only if theres a court descesion behind it
NO, until you are of legal age (in all states it is 18) and your parents have custody you can not do this, if you have reason and your sister can afford it you can ask your sister to have a custody hearing to switch and then you can.
Your Sister In Laws parents will be your Mother and Father In Law.
Train
It depends what you mean by 'of legal age'. Your parents have control until you reach your majority.
her sister
Tell your parents how you feel but the decision on who lives in their house is your parents. Your sister is an adult and can do what she wishes. Maybe they feel better having her close instead of kicking her out. This way they can keep an eye on her.
Sister.
In the cellar, Martha's parents are keeping abomination who is Jim, Martha's sister, Marys son. Her parents banned Mary from the house and sent her away. Her parents are ashamed of Jim so keep him in the cellar.
Well, if you know that she has a boyfriend that's great. But never let your parents know. Let your sister tell them. Talk with your sister and convince her to tell your parents.