I wanted to reply for the past couple of days but didn’t manage to. 
I realize that you’ve already gone through all the releases by Cézame Music, and I think that’s a good thing - so I’ll focus on saying why I think that.
I was still not clear on whether store information or cover artwork should be followed for digital releases, and I stumbled over what @aerozol wrote in another thread in September 2022, specifically about digital releases of which I don’t know if it has since been clarified into a style guideline:
One thing to note with digital releases, which that cover you’ve used as an example looks like, is that there’s no agreement that we should mess with the store-given title/change it to fit with the cover.
As an argument in support of your edits: the formatting of release titles on the Cézame Music website and on Spotify is often contradictory. The format “Title (Subtitle)” is shown on Spotify and “Title - Subtitle” on the agency’s website. So regardless of how the release titles are formatted on the Cézame website, the formatting doesn’t seem to be all that important to them as they roll out their releases to streaming platforms (and yes, there is the one or other Cézame release on Spotify that has its title formatted as “Title - Subtitle”, so it doesn’t seem to be an issue in how Spotify or some distributor handles that title data).
Because of that inconsistency in titling, I think your choice to format titles and subtitles according to MB style is good.
Now to go through all these edits and vote for them… Soon™.
I realized I’d ignored the last question in the original post:
Also - is it ok to add the missing (YYY) part from the label site to titles, which miss it?
Definitely! It’s on the cover, it’s on the label website. They seem to have missed those couple of subtitles on the way to the streaming platforms.