If I give up my parental rights to my child and their step parents legally adopts them am I obligated to pay child support anymore
Once a step-parent adoption is complete, you would not be liable for any current child support going forward. However, if there is an existing child support arrearage, you will most likely be required to pay that, unless agreed to otherwise by the other parent.
No, only if this occurs in Florida.
No. Once the adoption goes through then you do not have to pay any more current child support.