Hi, JM, welcome.
For #1 with the gallery images. Please see the attached screenshots (chrome-gallery.jpg & firefox-gallery.jpg) to see the difference in Chrome vs FF. I am on OS.
I tested your gallery page again, there are same list shown on Chrome and FF(screenshot: https://www.dropbox.com/s/froqeqietbu5z70/za-client.jpg?dl=0 ).
The gallery list rule is base on browser size(screen width or wrap width) and image self size. We use this plugin , there is not option to control list result. you have to change the image order, image size or remove image to change the list result
I think maybe there are different width window on Chrome and FF. Did you use same size browser width on Chrome and FF?
I did not resize the browser to get the gallery to disappear, it just seems to happen after being on the page for a while. I’ve only seen this happen in Chrome. (see attached za-galleryissue-chrome.jpg).
I opened the page url for while, there isn’t the issue. I remove the window resize function in main js file, please replace this js file by FTP, test again(clean browser cache or use private mode)
– download the attached file, unzip it
– login FTP, go to: themes/za-theme/js/
– upload / replace: custom.theme.js