yEd displays all successor/predecessor nodes in the successor/predecessor context views. Moreover, since those are context views, yEd does not display all edges but only those edges on the shortest path from (one of) the selected node(s) to a given successor/predecessor node.
I.e. yEd display all successor/predecessor nodes and the minimal number of edges to understand why a given node is successor/predecessor node.
Unfortunately, it is currently not possible to configure the edge criterion.