So still a very good fight for Inoue at super bantamweight and hopefully we can see this fight happening next year at least. And it might be good if Casimero will be the challenger, so that he will be extra motivated to pull an upset win.
As of now, his ranking is not yet considered to be a challenger to the champion, you can see the ranking here.
https://www.boxingscene.com/rankingsIt might take some time, but as long as Casimero continues to fight, he will eventually reach a level where he becomes the number one challenger. In the case of a mandatory fight, the champion would not be able to refuse it, as the organization could strip him of the belt.
Is that ranking already updated? Casimero won his last fight, so it's likely that his ranking has increased somewhat. However, since he fought an unknown boxer, the impact on his ranking may be minimal, and it's unlikely to propel him to the number one spot.
as of this ranking ;
https://boxrec.com/en/ratings?division=Super%20Bantamweight&offset=0&sex=MCasimero is currently ranked at number 2. Based on this information, it seems that this ranking is the most recent and up-to-date.