Hello . .
First I want to let you know that this kind of customization most likely require direct customize over the plugin which is usually disliked because the changes would be gone once the plugin is updated. Unless the plugin developer allows several extensions for their features :)
The good news that their map script is unminified version and map instances are accessible from other script. So if we intend to make some important changes without touching the js, it's still possible. You could check the instances from your browser ( on tab which contains the map ) by typing : javascript:alert([login to view URL][0]);
That where the map object saved, and I think that what we need to make these customizations. With my experiences in wordpress + js, I am pretty confident of completing this project.
Please consider and let me know what you think
Thank you,
Eni.S