The parenthetical remark makes no sense. Pantheism is NOT the denial of the existence of the universe. This is an invalid inference. Infinite in the sense of ultimate does not imply infinite in all respects. Also note that if God cannot change, then God cannot act, and God cannot create the universe because that is an action.
All actions involve change over time.
Action is required to be a person, so if God cannot change, God cannot be personal. This concludes my critique of your booklet. I now have some general remarks. When criticizing a view X and suggesting its replacement with view Y, it behooves one to understand view X in detail. In your booklet, X is atheism and Y is Christianity, but it is clear that you have done no significant study of atheism whatsoever.