The archives for the Moravian Church in America, Northern Province, are located in Bethlehem. According to their online resource guide, they have some records of the Allemängel congregation, but I'm not sure which ones. Contact information is on their website: http://www.moravianchurcharchives.org/index.php.

There's a biography of this family in the anniversary History of Lehigh County (Charles R. Roberts, et al., eds., 1914). It mentions a record in the courthouse in Easton (the Allemängel area was then in Northampton County) dating 17 March 1762, in which the children of Conrad Fry, late of Lynn Township, petition the court to appoint a guardian. You will find the volume with the Fry/Frey family online here: http://digital.lib.lehigh.edu/cdm4/beyond_viewer.php?CISOROO....

The children you list as being baptized at Allemängel were all in the younger group of children, so either the family moved there from somewhere else or the records had not begun yet when they were baptized. I did find online that the village of Fryville in Berks County was named after a Conrad Frey: http://www.windsortwp.com/windsor-township-history/.

There is an Esther Frey buried in the God's Acre cemetery in Bethlehem, Section D (Married Women), Row I, No. 17: "Esther Frey, 1747-1805, born at Allemaengel, Lehigh County, of Reformed parents; was baptized at her request, when 8 years old, against her father's will. She served in the family of Rev. G. Neisser, in Philadelphia." I thought at first this might be Conrad's daughter Esther, but since this was her married name, that can't be true (unless she married another Frey).
https://archive.org/stream/cu31924028862113#page/n91/mode/2u...