Howdy Bean,
First of all, I am just a simple user, but I will try to help you with your question. Anyway you can open a ticket via modmail in the TruckersMP discord.
Regarding the questions about the profile picture, I don't think anything will happen if two people have the same picture taken from the internet, as long as one doesn't contain the same name and descriptions of the other. But in the case of having a custom logo of another user, that rule §1.6 could intervene.
Regarding the user name, I don't think anything will happen if two people have the same user name, as long as each one has its own content and not copied from another person.
And regarding the last question, that is definitely not allowed, in any case you can not impersonate anyone, even if it is to do good things.
Best regards.