not legally
No. It may be illegal for you to have sex with him and since it is your parents house you can't legally move the boyfriend in without their permission but it's not illegal for him to live there. If he is also a minor and his parents don't want him to move in there could be problems.
They can only do so if the parents give their permission to do so. Otherwise they will have to wait until they turn 18.
Yes, unless his parents claim it because since you weren't married to him, it is not legally yours to keep.
In Oklahoma, the legal age of majority is 18. If you are 16 and wish to move out without parental permission, you would need to be legally emancipated by the court. Emancipation grants you the rights of an adult and releases your parents from their legal obligations towards you.
The minor female would need her parents' consent before she could legally engage in a change of residency.
18
No
yes
Yes
No she can not.
Not legally.