I searched, but didn’t see anyone ask this (or the search just sucks).
I have a JP album, with an English alias available. I don’t want to make a pseudo-release. Can Picard pull an existing alias from Musicbrainz and map it, like it can do with artists?
No, not currently possible. But there has been a recent code contribution that would enable translations of release and track titles similar to how artist names can be translated based on aliases. So this will come in one of the future versions.