There's no meaningful orthodoxy. All neo-pagan religions are neo-religions and the oldest of them dates from the sixties. They're based, primarily, on the counter-culture and orientalism of the 60s and 70s, gradually alloyed with more and more research material and archeological material as time goes on. The result is a weird mixture of hippie new-ager attitudes, intentional and unintentional white supremacy, 19th century romantic nationalism, christian beliefs that aren't identified as such, beliefs about magic dating back to Crowley, stuff cribbed from fantasy fiction, and idiosyncratic interpretations of fragmentary archeological information.

It's mostly a reactionary movement against Christian cultural hegemony wherein adherents attempt to create what they believe is an authentic, meaningful religion that provides them with the emotional support and purpose they did not find in Christianty. Many individual's have a "take that" attitude towards christian religion, with neopaganism being a form of self-assertion that they position as real and authentic, allowing them to dismiss a socially violent christianity that harmed them as false, dead, or inauthentic. In that sense it resembles many prior Christian heresies and could probably be studied in the same category of social phenomena as a christian heresy.

There are also elements of reaction against modernity, multi-culturalism, and capitalism.

In many ways it's a false consciousness of the violence of western cultural hegemony - capitalism and protestant christianity. Instead of confronting capitalism and it's super-structure neopagans retreat in to a reactionary fantasy of a golden age of authentic religion and meaning that they have conjured for themselves out of scraps and whole cloth.

All of which is to say, neo-pagans believe whatever things they want to believe. There's no orthodoxy or authority that could define an orthodoxy. As it is primarily a reaction against christianity many adherents beliefs are defined either against what they think christianity is or as what they think christianity should be but isn't. You get the macho "warrior religion" people who despise christians for perceived weakness, and then you also get people ostracized by Christianity's social violence who espouse pro-lgbt beliefs, celebration of sexuality, or alternate views on family that mainline christian sects reject. Many American adherents are seeking the "your own personal jesus" relationship claimed in christian fascism, but without the cultural violence of christian fascism.

To really understand where it comes from you need to look at the roots; 19th century romantic nationalism, fascist rejection of contemporary christianity, the counter-culture of the 60s and 70s, new ager mysticism, the "self help" movements, various 20th and 21st century magical belief systems. There are distinct origins for the modern neo-religions in the us and europe. In the us norse neopaganism was roughly the first expression and started with a neo-nazi writing from prison. Other strains evolved out of wicca later. In europe neo-paganism began a few decades later in the nordics as an environmentally focused alternative to bloodless nordic protestantism. Neo-pagan neoreligions have undergone a great deal of evolution since these originating strains without any authority or body of tradition to enforce orthodoxy, resulting in a variety of modern movements. There is often no authority within those movements, leading to even more variety as individual adherents build very idiosyncratic practices and beliefs.