Expanding on question 1:
Yes. You signed up from Lemmy.zip, who have their own set of rules for what is appropriate (as linked by trashcan). If you break them you'll likely be kicked out.
Furthermore, the sites and communities you interact with can ban you from talking to them: If the admins on the site I'm on (piefed.social) find your content to be inappropriate, they can ban your content from reaching users over here. That wouldn't affect you as much as being banned by lemmy.zip - it would just keep you from interacting with users and communities hosted at piefed.social.
Moderators of individual communities can also ban you, if they find that you break the rules in their community. If you're banned from a community you cannot participate in it any more.
Last, users can block you if they don't want to see your posts.
There's less of the funky shadow banning that Reddit does here, where your posts are rendered invisible to anyone but yourself without you knowing. I don't think that can happen at all.