If Christopher Columbus had never landed in North America, what would have happened to the culture, economy, religion, demographics and relations...

Of course, we will never be able to know for sure what would have happened if Christopher Columbus had not “discovered” the New World.  However, I am as certain as I can be that the course of history would not have changed significantly if Columbus’s three ships had been lost at sea or if he and his men had been massacred by natives when they landed.  Some European explorer would inevitably have come across the Americas and history would have played out roughly as it did in our world.

By the late 1400s, European countries had a strong incentive to explore and they had the best technology in the world with which to do dominate the people that they “discovered.”  European countries were hungry for spices and people who could bring those spices to their markets could make tremendous amounts of money.  For this reason, mariners were strongly motivated to explore and to see if they could find ways to get to places that had spices.  The Europeans were also motivated by the desire to find gold and other precious metals and to convert people to Christianity.  These things meant that Europeans would have kept exploring even if Columbus’s expedition had never returned.

If the Europeans kept exploring, they would inevitably have found the Americas.  If they found the Americas, they would surely have dominated its people.  They had technology that was vastly superior to the technology that the natives had.  They had guns, steel weapons, horses, writing, and other useful technologies that the natives lacked.  Moreover, they carried with them the germs of infectious diseases that would have decimated the native populations whenever they came in contact with Europeans.  In other words, there is no way that the natives of the Americas would have been able to effectively resist large numbers of Europeans for long.

With all this in mind, it is impossible for me to imagine any plausible scenario in which the Europeans did not come to dominate the Americas.  Because the Europeans would inevitably have come to dominate the New World, none of the things you mention would have turned out significantly differently if Columbus had never landed in the Americas.