Thank you so much for getting in touch, we really appreciate your time.
Polygons allow for some HTML to be added, however, does not include the text editor as the Polygons do so you will manually need to add in your HTML such as your links and so forth.
This will be getting improved in the next major version as it will include a full editor as with the marker info windows.
Additionally, you will need to draw the Polygon over the marker in order to have a marker present in the Polygon as the editor does not allow for markers to be added where Polygons already exist. Again, we are hoping to improve upon this in the future version of WP Google Maps.
I hope this helps?
Steven De Beer