The custom code is not part of the plugin because it is code specifically for your specific case of the theme you are using and it will not work for others.
The video is cropped because it adapts to the size and settings of the product photos so that you don’t have unevenness and bouncing of the design. There is no lightbox option to open the video you can use the Fullscreen button from the controls. I looked at your site now all seems to be working fine and as it should.
I will ask you if you have the desire and time to give a rating for the plugin, it is important for me to be able to develop the plugin. Thank you.