Hey @bleest, let's jump right into this!
When you say that your Dropbox used to show up under your iCloud in Finder, what do you mean exactly?
I'm asking, since iCloud is a different path, and one can't exist within the other. Can you send me a screenshot of the place your Dropbox folder used to be in?
As for the second issue, about the notification: Are you sure that you checked all the notification tabs on the Dropbox icon? Perhaps there's one you missed.
Can you also hover your mouse over the Dropbox icon, and confirm the version of the Dropbox desktop app, along with its syncing status?
Let me know more, and we'll take it from there!