Google Custom Map enhancement

Summary Version: Build of Javascript Google Custom Map to include an on-map overlaid legend and hover over description text for map markers. Longer Version: I have an existing Google Custom Map with Custom Markers built using the Google MyMaps app. This map is embedded within a Wordpress site already. I want to - 1. Add a permanently visible on-map legend overlay, similar to what can be seen here - [login to view URL] 2. Add hover-over text that appears when a map marker has a mouse cursor over it whilst the map is being accessed via desktop 3. Embed the map following the enhancements on both a Wordpress site and a html site I believe the necessary work involves use of Javascript and will result in an Embed Code and a Javascript file that will need to be implemented within the intended Wordpress and HTML sites. I will need help and instructions to understand how to perform the installation as I want to be able to do this myself so that I can embed the map on multiple sites immediately and in the future, for example following a Wordpress theme change. I have the Custom Map Markers ready to share. My deadline for the above is 12 November. I have no budget restriction. I am willing to pay any reasonable charge for the work. Resources: A. Link to Google Custom Map [login to view URL] B. Link to Wordpress Site with existing Map embedded: [login to view URL] C. Google Drive Folder with Map Markers & Job Spec [login to view URL]