These stories are true. But they do not have to be "literally" true (although they might if it pleases God to be so). And Jesus did not teach that they were "literally true" as well as he did not teach that they are not. He was not involved with XIX/XX century controversies of US Protestantism. At least not at that time.
When you read the Gospels, put the scientific issues of modern biology aside. The Holy Scriptures are not the scientific handbook. They are something much more important.
As razorbak said, one cannot be a Christian and not believe Christ. But Spiritual understanding is not available equally to all men - so it is possible for men of good conscience to disagree.
On the one hand, Christ spoke in parables so that only those who were supposed to understand, would (Matthew 13:10-17) - and certain things are not to be known (Daniel 12:4, Revelation 10:4, Matthew 24:36).
On the other hand, Christ chose twelve disciples who were each quite different and themselves had disagreements on the interpretation of Scripture (Acts 15) and He accepted with commendations and rebukes seven different churches (Revelation 2-3).
IMHO, the most helpful approach is to recognize a brother in Christ for his core beliefs in Jesus Christ and the Trinity and be understanding as he absorbs the Living Word of God under the leading of the indwelling Spirit. This is how we are all, individually, to learn (John 15-17, Romans 8, I Cor 2).
But if a person claims to be a Christian but promotes a doctrine which denies Christ (as the author of this article has done) - then we can pray for his spiritual recovery from the delusion (Romans 1) – but we must not encourage him.
My two cents...
Jesus made it clear when He was teaching using parables.
If these OT stories were NOT literally true I believe Jesus would have made that obvious. I don't believe Jesus would have left us guessing.