A husband and wife who allege they were the subjects of an unjustified child-neglect investigation got the go-ahead to pursue their claim that their constitutional rights were violated. In a written opinion, U.S. District Judge Robert M. Dow Jr. declined to dismiss two former officials with the Illinois Department of Child and Family Services as defendants in a lawsuit filed by Gina and Roman Churnovic.Dow did not rule on the merits of the couple’s argument that the investigation that followed their refusal to approve …