When I edit a ZObject's ext-wikilambda-about-edit-metadata label, short description, and aliases, I only see the field labels and empty editing fields. It would be much more useful to also see existing labels, descriptions, and aliases in other languages and translate from them.

Which languages to show? Probably English (because the page Help:Multilingual kind of says that it's the authoritative one) and the fallback language (if it's different).

When editing labels, descriptions, aliases in Wikidata, other languages are usually visible, but the design in WikiLambda is different, and they aren't. It's very inconvenient to translate those things from memory, especially the descriptions.