How does Hellenismos differ from Wicca and Wicca-influenced neopaganism?
The only real link is that they are both non-Abrahamic religions, commonly described as “pagan” (although even this is not universal). Otherwise, they differ as much as Shinto and Christianity differ, which is to say, on almost all counts. They have distinct historical origins, different theological perspectives and worldviews, and very different styles of ritual. In short, the two religions share nothing with each other that they don’t also share with other religions. (Which is not to say that they cannot cooperate in multifaith efforts on issues of common concern, of course.) Religions that share some closer theological links with Hellenismos include most of the reconstructionist religions Asatru and related heathen religions, Religio Romana, Romuva, etc. and some indigenous/ethnic religions.