I logged in to your site and first checked your setup. Here are my answers to the points you've brought up in your first post.
1. Your sticky bar's background semi-transparent. You should set it to solid (see secure note below)
2. I am not experiencing this issue. Would you mind providing a screenshot of what your seeing on your end? Also try other browsers and see if the issue persists there. Then, give us the OS and browsers you used and their version number.
3. Your gallery lightbox is powered by a third party plugin. Please contact the plugin's support.