After a nissen fundoplication takedown, should the normal esophagal motility priorto. Surgery return?

Yes. When performing a nissen fundoplication, the esophagus is only marginally affected. Therefore, following reversal your esophageal function should return to your pre-surgical state. This is best determined by a motility study.
Likely not. This is a complex question. Without knowing what your esophageal function was like, and why you had the surgery in the first place, and your symptoms prior to the take down it's impossible to predict how you are going to be after the reoperation.