the jlmessages option has been replaced by showJLMessages. This will change the default state of the checkbox option, leaving users the possibility of changing it.
Sorting must now be specified in the settings file (avc_settings.xxx). Setting defaultsort to camsontop will place users that are streaming on the top of the list
I was not able to replicate this. Can you post a screenshot so I can see exactly?
Regarding JL Messages: these are system messages and the styling is directly controlled by the theme.
Regarding the translation and config files, since you are updating from such an older it is more likely that there are lots of changes. For now, there is no other solution regarding the translation files, however for the settings file, you can create an integration.php file and place all the settings there, leaving the avc_settings.xml file unotuched. This way, you can replace the avc_settings.xml file without having to worry about restoring settings from the previous version.