In most cases tea does not dehydrate you, contrary to popular belief. But, tea can potentially dehydrate you depending on how much caffeine is in the tea and how much tea is consumed. Read more for details.
According to the University of Maryland Medical Center (UMMC), licorice root does have the potential to be dangerous if consumed excessively. Learn more about the benifits and dangers of licorice root tea.
Fresh herbs are not necessarily “better” than their dried counterparts for making tea, however, I do find that fresh herbs produce a certain “brightness” in the flavor of the tea. Click on this article for a list of fresh herbs you may want to experiment with steeping and blending.