The first of each of those two listed styles can’t be deleted (presumably because they’re in use), but the other ones can.
I do not know what is different about my computer, but none of the options light up the trash bin. Perhaps when the next version of Dorico comes out the results will be different.
Since it is not a fatal error, I can live with it until then.
Thank you, Daniel, for the time you have spent looking at this.