No two religions are alike, therefore both cannot be true.
But religions are in fact very much like each other in many regards. Just as no two humans are identical to each other, they do share more than a great degree of similarities that do make the relatively all the same. We speak about "human nature" all the time. We all deal with things like loss, fear, hope, faith, anger, health and disease, ideas, and so forth, that makes us all human together.
Same thing with religions. While no two religions are 100% clones of each other, like humans, they do all share the majority of things in common to consider them essentially the same.
There is a God, or there is not.
Not quite so simple there. First, you will find that all religions do in fact share a belief in some "higher power", in some form or other. There are no "atheist" religions per se. Even Buddhism which does not speak of "God" in the sense of a personal deity form, does speak of Emptiness, which is directly equivalent to the Christian theological understanding of "godhead", the Infinite essence of all reality that we call "God". Taoism speaks of the Tao. Same thing. Hinduism speaks of Brahman. Same thing.
Just because the same thing is referred to with different language, that does not make it something else. Some people call flavored carbonated beverages as "pop", some call it "soda". Different words, same concept.
Man is need of salvation, or he is not.
Again, all religions teach this in one form or another. Same basic general concept. Buddhist speak of ending suffering. Hindus speak of fleeing the world of illusion and finding the true Self. Christians speak of being saved from sin and uniting with God.
Jesus Christ is God's son, or he is not. Jesus is the saviour of the world, or he is not.
Even this concept of God incarnate is found in other religions as well. They can be understood as Avatars, God revealing himself through human form to other humans.
Even a Christian can recognize within their own Christian teachings from their own prophets and apostles, that God can and does reveal himself to others in the whole world, without the need for preachers on street corners. Many passages in the book of Romans explicitly details this. So one could in fact understand that as God manifesting himself to others in the same ways he manifest himself in Jesus.
Again, different words, or different names, for the same basic thing.
There is a heaven and hell, or there is not.
Again, all religions pretty much have this general concept as well. Heaven is pointing to unity with God; hell is pointing to separation from God. All religions are at their heart about restoring that Unity, from our lived experiences of separation from God.
Only one faith and wisdom can be true.
Which is shared by all religions, spoken about in different ways in different languages.