I couldn't reproduce the bug with the registration. I created a new identity account and the registration to the wiki worked. Did you do something special during the registration?
For the translation bugs, I think this is a problem in the job queue. I think we are using the default settings, but MediaWiki has some recommendation (creating a cron job). I will discuss this with Ben.
The login problem is something I found on an old dodo list, it may have been solved a long time ago - I included it just in case. I'll remove it from the list. The e-mail settings problem also seems to be ancient history.
Yeah I'm now in vacation, so I started looking at the issues. Some are already solved.
The login problem is probably not solved (I didn't modify the phabricator extension), but the phabricator login will need to be replaced by a gitlab login anyway.
The list numbering problem is very strange, I have the same problem with Firefox but not with Chromium.
Is the Special:WhatLinksHere problem still here?
About the language in the search, it should be possible to filter with: https://www.mediawiki.org/wiki/Manual:Hooks/SpecialSearchResults but it will be difficult to get the user language and not having false positive.