question 4 - during the configuration wizard there was the option to get different domain names for different languages. At this point I have no interest in that, but later on that's definitely something I'd want. If I want to switch to that later, is there any way I can do so? I couldn't find it nowhere in the settings and I can't go back to the installation wizard either.
You can switch to the "different domain per language" URL format anytime you want from WPML > Languages > Language URL format (Please see the attached screenshot).