Thank you once again for you great support.
Regarding the placement of the js' in the footer, the clue could be again in the MapPress Easy Google Maps plugin, because it loads its 2 js' after the </head> and <body>.
In addition, please have a look at the following Google's Performance Best Practices:
Prefer asynchronous resources
Regarding the gmaps-frontend.js, I am reorganising all my maps on the EdWeWo.com to utilise the only 1 maps plugin - your plugin with 2 js'. That will reduce the number of DOM elements by 33% and also improve a Web Page Performance by 33%.
Please have a look at the EdWeWo.com new contact page, which is now utilising your plugin with 5 different maps (1 OpenStreetMap and 4 types of Google Maps) presented all in one display:
By default all my maps are Google Maps now, but I will still use OpenStreetMap Maps to make "FREE 3D Maps" videos like the ones on the EdWeWo's YouTube Channel:
Also, I wanted to utilise the multi layer-maps to install faster all my markers and all my layers back to the EdWeWo.com, but unfortunately displaying a list of markers under the map is not available on multi layer-maps. It will be great if you could please add a feature to display a list of markers under the multi layer-maps too!
Finally, It will be really great if you could please add a feature for pop-up text to be visible by default on layer-maps too!
P.S. I have just placed my vote (works # 2) for your v2.6.1 release on wordpress.org!