My answer would be no, they're all very different to each other. What they teach, how they express their beliefs, ethics and rituals are very different and one can find a lot of contradictions.
The commonality, to me, seems to be less in the religions but rather in what led to religions. I may be wrong, but my interpretation is that people try to understand reality, forge an ethical code, find ways to improve themselves, make rituals based on valued events, and so on. Since there's so much diversity on our planet, cultures, individuals, and so on, it's no wonder that we ended up with so many different religions! I don't think there's anything wrong with this unless one tries to impose their own reality onto others.
Hope this is clear enough so that there's no misunderstandings. I'm not saying it's all invalid and fake, it's a subjective reality which is very valid, something I'm trying to find and understand for myself as well (it's not easy).