Managing content for multiple users within ArcGIS Collector App?

You can limit editing by user so that users only edit their features:https://doc.arcgis.com/en/arcgis-online/share-maps/manage-hosted-layers.htm

For user specific data access controls I have seen a demo where the server dynamically filters the response data based on authenticated user. This was done with custom ArcGIS Server SOE developed by Esri Professional Services. I don't know if it works with Portal / hosted services. Ask your rep.

Obviously this would not available in ArcGIS Online.

There is an automated map publishing solution that could be used to generate the maps with individual query filters for specific users. http://solutions.arcgis.com/shared/help/automated-setup/