Style guidelines on "feat." join phrase has been abandoned after https://community.metabrainz.org/t/guidelines-on-feat-join-phrase-style-671/206449.
Both guess case and guess featuring artists have to be updated to reflect this.
The only remaining orthographic change is to append a full stop after "feat", as in "feat.". This follows the error correction guidelines only, see
STYLE-860 for reference.