For example, if I try to save this message:
There are around 70 messages in the 'Wiki Editor' group that require this permission. How can I enter these translations? Could I request for the 'interface-admin' permission, at least on a temporary basis, or is there some place where I save the translations to be entered by someone else?
I confirm this problem (I'm a translator admin too, but cannot edit https://translatewiki.net/w/i.php?title=MediaWiki:Wikieditor-toolbar-help-heading-description/gom-latn&action=edit because of this lock).
What you can do is to prepare a list of those message in a thread on your talk page, with links to these messages, then your proposed translation.
Then ask to a site admin (here in this Support) to insert these translations (make sure you give the correct language code at end of each link going to the edit page that you see locked): give him a link to your message thread.
This is another effect of the recent "incorrect caching" bug in this wiki since September (which occured in the "Memcached" server, not in the SQL server itself). When I visit https://translatewiki.net/w/i.php?title=MediaWiki:Wikieditor-toolbar-help-heading-description/gom-latn&action=info (from the "information about this page" link in the side bar), I do not see any cascaded protection.