Every serious religion worth considering is different and distinct in its fundamental core claims, even if there is a significant influence and overlap on other levels.

No amount of pseudo-philocophical and quasi-historical research can change this basic fact.

Naive attempt of some buddhists to reduce (in their eyes of course its the highest compliment) other religion figures to mere "buddha" label is nothing but silly, laymen kitchen theology. It is disrespectful to both buddhism and other religion.