Of course not. They only defend those doctrines Fundamentalists fine hard to understand. Everything else (especially in the "old testament") is negotiable.
Patently false. I would once again refer you to the Catechism. One of the most concrete non-negotiables is the substance of the fall of Adam and Eve, and the protoevangelium which followed.
As far as mentioning Catholics (they) defending Fundamentalists doctrines the average Catholic of the 30% attending Mass on Sunday would not know the first thing about those doctrines. As it is the attendees do not know that much about Catholicism.
After teaching CCD for many years, the average youngster completing CCD is taught that God created the universe and everything in it. It is not until they are older and get caught up in their liberal educations that they lose track of the Old Testaments and its truths.
The first question in the Baltimore Catechism is, "Who made me?" The answer is, "God made me." Right out of the Old Testament.
The second question is, "Why did God make you?" and the answer is "To love Him and serve Him."
I learned that 70 years ago.