yes
If the father of your kids moves in does he still have to pay child support?
You still have to support her until she is emancipated or the law or child support agreement says stop.
The child support goes to the one who have custody. If the grandparent still do and the child has just moved out temporarily, they will still get it. If the child is under 18 and has moved they also still get it unless the child is emancipated. If the child is 18 the child support generally end but it depends on the state laws and/or what you have written in the child support agreement.
No, child support is only owed to the custodial parent/guardian. If the grandmother has become the custodial guardian, child support will be owed to her, instead of the mother.
YES, BUT YOU CAN FILE A PETITION FOR MODIFICATION OF YOUR CHILD SUPPORT
Depending on the state, yes. see link below
Yes.Yes.Yes.Yes.
it goes directly to the child.
If the obligor still lives in the US, they retain jurisdiction. see links below
Yes, but you can file an injunction to have the child returned. see link
Yes, If it is back child support than it is already owed. Sorry.
Yes, they are a minor