Hello,
1) You can translate it using Loco Translate. You just need to synchronize translation files after update to get new strings.
2) We provide base support for the plugin options but if you need advanced support you should contact with plugin authors. Only plugin authors are able to fix plugin bugs.
3) Only by additional customization. Add custom class for the group where you want to have 3 fields per row and change the width of the fields. You may also contact with plugin author to ask if they have any other solution for you.
4) We have changed the carousel on your test site (You sent link and access in chat). Please, check it and we’ll move the changed files to your live site if everything is ok.
Regards