They can't simply "give the child to you." You need to return to the court and have the custody order modified so you'll have legal custody. It will go easier if the current custodial parent consents to the modification. At that time the current support order should be terminated and you can request child support if you wish.
what if the noncustodial parent still reside with the custodial parent, is noncustodial parent still obligated to pay childsupport
Yes. The marital status of the custodial parent change does not change the obligation of the noncustodial parent.
Yes. The fact that the custodial parent got married has no impact on child support.
Yes. They are still the child's parent and responsible for supporting their child.
The State in which the child resides.
If the noncustodial parent tries to keep the child, the custodial parent can get the noncustodial parent charged with kidnapping and contempt of court both can be jail time for the noncustodial.
Not from SSI, only SSDI.