Best approach for the Design Pattern for multiple schedulers using interface and abstract class
It seems not a good idea to hard code the different constants. I would inject them through the constructor (I am using properties instead of Get-methods):
public sealed class Publisher : interfaces
{
    public void Publisher (string userType, string dataType, Timespan interval, string url)
    {
        UserType = userType;
        DataType = dataType;
        Interval = interval;
        Url = url;
    }

    public string UserType { get; }
    public override string DataType { get; }
    public override Timespan Interval { get; }
    public override string Url { get; }
}

Then create a factory
public static class PublisherFactory
{
    public static Publisher CreateCustomerRetroPublisher()
    {
        return new Publisher(&quot;Customer&quot;, &quot;Retro&quot;, Timespan.FromMinutes(2), &quot;CustRetroUrl&quot;);
    }

    ...
}

If you need different behaviors for different publishers, you can inject them this way as well. For instance, inject services for timeline-specific behavior (through a ITimelineService) and user type-specific behavior (through a IUserService). Like this you can combine the different behavior types in different ways. 3 timeline services + 4 user services = 7 services is better than 12 different classes.
The constructor would then have additional parameters
public void Publisher (string userType, string dataType, Timespan interval, string url,
    ITimelineService timeLineService, IUserService userService)

The services can be assigned to private fields, as they do not need to be visible publicly.
See also: Composition over inheritance (Wikipedia)