Third party keyboards would certainly let you edit the predictions. For example, in SwiftKey if I see an unwanted prediction in the suggestions I just long-press it and it asks for confirmation that I want to delete it.
On my phone (HTC) I can edit predictions for the built-in keyboard from Settings > Keyboard (select the built-in one and there's an option to edit the dictionary). I've no experience of Note 5 software though, so can't say whether that's an option (if it's not in the keyboard settings and a long press on the prediction doesn't give you the option then probably not - they shouldn't make it too hard to find).