Help Needed w/ Data Model :-(

ki 

Ok, so here is the model for the sample data you provided. 

I take it that what you are trying to achieve is a table showing employees who are in the success plan, correct?

If so, we need a measure which will filter the learning plan table to show only the learning plan IDs included in the success plan table. We can then filter the learning plan status to show only these LP IDs and see the corresponding employees

The measure we need is:

SP to LP IDs =
COUNTROWS (
    CALCULATETABLE (
        VALUES ( 'learning-plans'[LP ID] ),
        RELATEDTABLE ( 'success-plans' )
    )
)

We can now set up the visual using:

Learning plan [LP Name] (I'm using 'Learning plan[LP ID] because it´s easier to see what's going on)
Role [Employee Role]
Employee [Employee Name]
Learning status [LP status]

Select the visual, and add the [SP to LP IDs] measure in the "filters for this visual" in the filter pane and set the value to 1.

And you get this:

 If you only want to show the "completed" status, just use the field in the filter pane (or use a slicer):

I've attached the sample PBIX file for your reference