Thank you very much for the assist.
As it turns out, the modification you provided didn't quite get the desired result. I'm unable to explain why, though I really wanted to dissect the issue, for my own education. The sticking point seemed to be getting the UNCLICKED buttons to return back to "normal" brightness.
In any event, I now have the complete code to accomplish what I wanted and I'll share it here, in case it helps others in the future:
Sub Add_Row_Field()
'Author: Jon Acampora, Excel Campus
'Swaps out Row Fields, via a button that has the macro assigned to it
'Remove all Row fields and add the Row field to the pivot table.
'The field is determined by the button text that calls the macro (i.e. name the button with the EXACT name of the Field that it's assigned to)
Dim pt As PivotTable
Dim pf As PivotField
Dim sField As String
Call SetColor(Application.Caller)
For Each pt In ActiveSheet.PivotTables
'Set variables
sField = ActiveSheet.Shapes(Application.Caller).TextFrame.Characters.Text
'Remove existing fields
For Each pf In pt.RowFields
If pf.Name <> "Structure Level 02" Then ' This is the line that makes the Level 2 Row Field stay in place
pf.Orientation = xlHidden
End If
Next pf
'Add field that button was clicked for
pt.PivotFields(sField).Orientation = xlRowField
pt.PivotFields(sField).Position = 1
Next pt
End Sub
Sub SetColor(v)
Dim cell As String
cell = ActiveCell.Address
ActiveSheet.Shapes.Range(Array("Rectangle 23", "Rectangle 22", "Rectangle 21", "Rectangle 13", "Rectangle 10", "Rectangle 1")).Select
Selection.ShapeRange.Fill.ForeColor.RGB = RGB(44, 44, 44)
ActiveSheet.Shapes(v).Fill.ForeColor.RGB = RGB(224, 255, 124)
Range(cell).Activate
End Sub