Agreed.
Very unlikely
That’s a leftist fantasy. The neo-nazis are confidential(very little groups) and they rarely(or never)made this kind of actions.
In addition,above all, right-wing parties are gaining big votes in the last elections(Finland, Sweden,Norway, Denmark...in eastern europe and probably western europe...)
No need to doubt. If he is a Christian, even the most zealous of believers, he would not have been able to justify his actions on Christian grounds.
That he is a neo-nazi is certainly true. All muslim fanatics are neo nazis. That is the foundation of modern muslim terrorism. Referring to him as somehow conservative twists the meaning of words into unrecognizable goo. The heart of this horror has yet to be documented.
I would note that neo-nazi motivations put him in the same broader category with Marxists and jihadists, all of which are opposite and antithetical to Christianity.