Don't bother arguing, then. Let's not get riled up. Block and ignore if they come to your wiki. If they create new wikis... that's Fandom's worry, not yours.
Fanon and canon have nothing to do with it. "Official" is not a label you can slap on your wiki to give it more credibility; it's something only done in partnership with the IP owner (as mentioned). They're just as unofficial as the old wikis. In fact, your wikis should probably be deleted as duplicates.
Edit the existing wikis.
Unless it's added natively to MediaWiki in the future, I wouldn't count on it. And if it is, add another 5 years before Fandom updates to that version. There are a lot of issues with Fandom and they waste enough engineering hours on non-essential features.
They won't. They might just crash the brains of obsessive cleanup admins though. Double renames are rare and the only ones I heard of happened because of a glitch. On the surface, there was nothing wrong. But in the maintenance category, there were broken and double redirects that could not be resolved. On every wiki the user went to.
It's a rule because it's a technical limitation. MediaWiki was created decades ago, before the whole concept of social media and name changes took off. Changing a username requires a bot to go through all your global edits, and that could take a lot of steam. Changing it twice leaves a ton of double and broken redirects across wikis.
Having said that, image cropping is off and there has been a ticket for that. Reported it ages ago.
The Theme Designer recommends 1880p wide (and square for a full background) but on DesktopXL, it tends to cut off about 100 pixels on the right. There are css fixes, but they won't work on Discussions.
No, you can't. At most you can point out this flaw in a contact form and hope there's a site-wide change.
You can change the background with the ThemeDesigner.
Depends on the context, and local attitudes. On busy wikis, it can be as little as a week.
I've had pings on threads from years ago. I got one from 2013 last year, IIRC. The thing is, these discussions are dead. There's nothing useful to add to them. If it's a social issue, it's resolved. If it's a technical issue, it's probably a new issue. Unless you're very late with a reply or clarification on your own post, you're just wasting everyone's time.
There's really not enough information to give you an answer.
Sockpuppetry is using multiple accounts in bad faith, like pretending to be multiple people (to rig a discussion or vote) or to evade a ban. There are legitimate reasons to have multiple accounts too.
The way Fandom is set up, accounts aren't really created on one wiki, or for one wiki.
It does that when you're in Discussions, when the sticky navigation bar overlaps with the Mark as Read button. It's annoying, I reported it as a bug ages ago and even then it was already known. You can still click it by scrolling to the top.
There's a "Mark All As Read" button, and you can unfollow discussions.
Vandalism is easy enough to revert, but that's irrelevant to the punishment. Vandalism is always easier to fix than it is to do. It's their own time they're wasting.
No you don't. You're banned. Creating a new account doesn't mean you're unbanned, it means you actually break more rules. Hard rules. Global rules. and get banned again.
All en wikis that start with "Capsule"
How are you looking for it? Smaller and newer wikis may take some time before they end up on Google.
If you've edited before, go to Special:UserActivity.
You are not owed a warning. Unacceptable behavior is unacceptable behavior.