The criteria for a valid court?
As explained above the Peruzbal is only effective if it is performed before a valid court of law. A valid court consists of any three Kosher Jewish men.
 Admur 35; Rama 67/18 “One may be lenient in these times”
Other opinions: Many Poskim rule that regarding a Peruzbal the court is only valid if it is a prestige court that consists of three Jews that are expert in the laws of a Peruzbal and Shemitah and have been appointed by the townspeople. [Michaber 67/18; Rambam 9/17 based on Gittin 36b “A Peruzbal can only be made by a court of law equivalent to Rav Ami and Rav Assi.”]
 Meaning that he has not done a transgression which invalidates him from becoming a judge, as explained in the Choshen Mishpat Chapter 7 regarding judges and Chapters 34 and 45 regarding witnesses and the same applies for judges. [7/9] Practically this includes all standard Orthodox Jews.