Yes, religion is necessary for humans. If there will not be religion, There will be no morality or moral values.
Not true. You are suggesting that anyone who doesn't follow a religion is immoral, which is clearly not the case.
There will not need for building good character. There will be no concept of the day of judgment. So everyone will be free from all kinds of divine rules and regulations.
It is impossible for someone who believes that good people go to heaven to commit a good or selfless act, because it is impossible to separate the act from the prospect of personal reward for doing it. It is only possible to commit a selfless act if you do not expect a reward for doing so, i.e., if you are not religious.
Man will not be a super creature. His status will be like an animal.
Man is not a super creature. Man is an animal. There would be far fewer atrocities and less suffering in the world if people stopped thinking of themselves as being innately superior to other people or other animals.