Carsten, intriguing yes, but perhaps not surprising. My take is that most religions have a lot in common, because they are manifestations of a need to collectively organise an interpretation and understanding of the world on the one hand and to codify the way we have to behave in order to live together successfully on the other, i.e. ethics are emergent from the hard-wiring of humans as self-aware, social and cooperative beings. Likewise the significance of "the word" can probably be put down to an early instinctive understanding of the role of language in shaping our minds and the human experience, indeed in making us conscious in the first place.
The root of commonalities in terms of cosmology, creation myths and metaphysics can be found in universal experiences e.g. the need to explain natural disasters, the dualities of life/death, night/day, sky/earth, land/water, heat/cold, male/female, etc. Similarly the commonalities in ethical systems are down to shared emotional responses (which are explicable in evolutionary terms), e.g. empathy for someone in pain and the desire to alleviate its cause, indignance at injustice, guilt at causing suffering in others, etc.
I agree with Glenn's point that spiritual and scientific teachings don't directly contradict each other since they operate in different modes (ships that pass in the night) but there are some inherent tensions between the religious and scientific world views. e.g. the emotional/ethical responses mentioned above aren't entirely universal but when they're lacking we can either look at explanations such as childhood trauma or brain damage to explain the absence, and try to treat through therapy or medication or surgery, or we can posit possession by evil spirits and try to treat with exorcism. There will also be significant differences in the criteria, methodology and evidence we will use to assess the success of these different approaches.
Just my 2p/2c of course