An anti-Abrahamic is a person who is opposed to Abrahamic religions or doctrines.

The Abrahamic faiths are Judaism, Christianity and Islam. Lutheranism is a form of Christianty. Therefore Lutheranism is an Abrahamic faith. That is an example of a classical syllogism.

That all depends on who you ask. Anyone's beliefs are considered mythology to someone else. Mythology is simply a collection of stories that describe supernatural events that help explain origin and purpose of life. They often times of various gods and angels or demons or other such creatures interacting with man and shaping the course of human events. The stories of the bible are considered Abrahamic mythology to non-believers of the bible for instance.

By definition, Abraham (from whose name the term "Abrahamic" is derived) was monotheistic. He had one god.

Therefore, all Abrahamic religions follow the god of Abraham, who has many names. They probably wouldn't be Abrahamic if they did anything else.

Abrahamic