No but they are still there for you
As he's 19, they do not.
well, you cant but your parents can.
Yes. 18 is the legal adult age.
Yes, that should not be a problem with parental consent. However you will not be legally emancipated with full rights as an adult -- your parents will still have legal custody -- unless you go through that process with the courts.
Yes IF the 17 year old daughter is still under the parents custody. If they have been disowned, or have disowned their parents, or are under the legal custody of someone else, such as a grandparent or other person, then the biological parents cannot get in trouble, but if the daughter is still under their custody while living elsewhere, she is still in their control by the governments standards and they can still be in trouble.
Parents do not have a legal obligation to provide for adult children who still live at home. However, parents may choose to establish guidelines or expectations for their adult children living with them, and may have legal responsibilities related to providing a safe and healthy living environment.
That depends on where you live and your custody order. Were you granted temporary custody with parental rights intact? Were the parents divested of their parental rights and you were granted sole legal and physical custody? There are all different kinds of custody agreements and they can be modified. Refer to your documents or seek the advice of an attorney for an informed opinion.
No, once you turn 18 you are a legal adult
Yes, they can, but you don't have to submit to it. If you are still living in your parents' home, you should keep in mind they don't have to allow you to stay there if you are an adult.
If they have legal custody, they are, by definition, the legal guardians.
You haven't provided his age or the details of the "other family". He can make that decision when he reaches eighteen years of age. If he is still a minor the parents in the other family would need to establish legal custody in the court where you obtained custody. You would need to relinquish custody.
Technically your parents will always have custody over you. But if you are a citizen then not really.