Hi Steph,
SimpleMarkerOverlay is easy to be used, but you can implement more custom logic for FeatureSourceMarkerOverlay.
For the sample DynamicOverlay it shows display data as markers with different styles based on its attributes.
About your option 1:
It looks your code for the button is not in MainWindow.xaml.cs, so I don’t know how you implement it, but I think if you put the button in a layer, you can put this layer into a custom overlay, then set visibility for different level to make it show or hide.
About your option 2:
In fact you don’t need marker I think, you use the CustomizedPopup now, and a marker should be implemented just like a point, you can use an InmemoryFeatureLayer, then draw the point by image, when you click on layer, find nearest point, and popup the CustomizedPopup about it.
If you implement that, you can put this layer into the same overlay which contains your control point layer, and then they can be set hidden status at the same time.
About the performance, if you found its slow, you can do some optmize about it for example: open cache for base overlay, only refresh necessary layers etc. I don’t think this layer will cause this problem. And we can discuss about that after you implement the functions.
Regards,
Ethan