Great @josefkreitmayer, thanks for the summary
If you can give me examples of typical images in category 2, I can tell you roughly whether they might be accepted or not in commons. High-quality images are obviously preferred, but there is a lot of variation in quality, as you might imagine, especially considering that it’s a volunteer-based project.
As for #3, note that the license of a logo has a different purpose than the trademark. It is perfectly viable to have a freely-licensed image (which can be used to, for instance, illustrate the Wikipedia article on the company) while maintaining a trademark policy that regulates its permissible usage. See for example the Wikimedia logos themselves, which are freely licensed and also covered by this trademark policy.