Final answer:
The recommended edit tool for updating the coastline feature class due to erosion in ArcGIS is Reshape Feature.
Step-by-step explanation:
The recommended edit tool to update a coastline feature class in ArcGIS due to erosion is Reshape Feature. This tool allows the user to modify the shape of existing features by adding or removing vertices along the coastline. By reshaping the feature, the changes caused by erosion can be accurately reflected in the feature class.