1.You can use a translation file (using POEdit to change the data in languages directory) to change to any string you like. If you do an update in the en_US.po (or another depending on your site language) file, you should see strings like details, expand etc. in the strings list available for translation. You would then be able to input any alternate string of your choice there.
Then you can change it in theme files , Pls find the strings in framework/functions/thumbnail-functions.php and modify the strings accordingly. Pls use child theme to preserve the theme file changes otherwise ll lose the changes once you update theme.