1. The answer to your question can be found in latest Release Notes.
2. Your Lightbox setup targets all images. The Selector should be specific. For more details, please review the Lightbox documentation: https://theme.co/apex/forum/t/shortcodes-lightbox/165
3. Images in V2 Elements include the width and height attributes. If you're using a Classic Image though, you need to change it to V2 Image as there's no way to add attributes to it. Images used as background are added by CSS so width and height attributes can't be applied to them.
Hope that helps.