On the Wikidata side it’s a bit of a mess, and removing “wrong info” would entail a lot more than just changing the MusicBrainz identifiers. There is no “official” convention for how music data is organized, which means that basically every item for 20th and 21st century music that wasn’t edited by myself or @Moebeus represents more than one MusicBrainz entity; e.g. albums tend to have identifiers that refer to different editions, and singles are almost always conflated with songs. This is partly a consequence of imports from Wikipedia infoboxes, in which songwriting credits are combined with production credits, audio snippets, singles chronologies and YouTube links.
I did draft an RfC which would be an attempt to formalize a MusicBrainz-esque ontology, but there is a lot of work to do before anything is usable; e.g. there should probably be a separate property for specifying main/featured artist credits, but the property proposal discussion has been stalled (derailed, to some extent).
Going back to the “wrong info” thing, the easiest way to fix the item structuring problem in Wikidata would probably be to import whole items from MusicBrainz (probably release groups, recordings and works), which would also involve editing and/or merging existing items to maintain the current data. This would, of course, involve dealing with a fair amount of other issues at the same time.
(earlier discussion: Links to Wikidata)