As long as they have the other parents permission i think.
No, you cannot move a child out of state if you have joint custody.
Only with permission from the other parent and the court.
With an injunction
Not without permission from the court with agreement from the joint custodial parent.
File an injunction ordering the child be returned. But, be prepared for a false allegation, which is common in these cases.
The guidelines are basically the same in every state but obviously there are a few minor differences. Joint custody consists of Primary Custody & Secondary Custody. The parent with primary custody is who the child lives with & the other parent has secondary custody. Depending on the age of the child & the state in which they reside, the court may let them determine where they choose to live. Or if both parents agree on the child's decision then the child can live with either parent.
You may since sole custody implies the child lives with that parent 100% of the time. With joint custody the child may dwell with the other parent for part of the time or with one parent all of the time with visitations for the other parent. It depends on the details and the state child support guidelines.
Joint custody is a court order whereby custody of a child is awarded to both parties. In joint custody both parents are "custodial parents" and neither parent is a non-custodial parents, or in other words the child has two custodial parents.
Not without permission of the judge/court where the custodial order was issued.
The other parent could get sole custody.
Just on vacation should be fine but he would need your permission if the court order can not be fulfilled or if he moves with the child.
No, you can't, especially if you have joint custody, that will be considered parental kidnapping.