The natural harmonic you are evoking in the Violin is not typically notated with a degree sign as the node (fingering) does not correlate with the resulting sound. These types of natural harmonics are typically written with diamond noteheads. This can be achieved using the settings in the attached screenshot.
I have provided two types of notation to represent the string indication. Currently, only the first is native to Dorico’s ‘harmonics property’. The second has been discussed Suggestion: Another Natural Harmonic Notation style - Dorico - Steinberg Forums
As for your Double Bass harmonics, they will always show in red because Dorico does not currently support scordatura at the moment (the red colour, however, isn’t visible upon final PDF and normal printing).
