Your commented out Location properties have the Y value set too high, so the controls are not visible on the form:
'.Location = New Point(20, (475))
'.Location = New Point(100, (470 + (10 * count)))
The Location of the control is in relation to the parent's client space, so use smaller numbers:
With newTextboxLabel
.Text = itemList(count).textboxLabel
.Location = New Point(20, 20)
.AutoSize = True
End With
Dim newTextbox As New TextBox
With newTextbox
.Name = "Textbox" & count.ToString
.Size = New Size(100, 20)
.Location = New Point(20, 40)
End With