Occam's razor is simply a posit that if an observation can be explained by many plausible explainations, the simplest one is more likely to be the correct one.
Correct. Which is why the idea of the earth moving around the sun in an elliptical orbit is preferred to the complex Greek model.
Science is about testable results, a theory must be testable in order to be considered useful to science. How would one test reincarnation with an scientific experiment?
Science is not necessarily about deliberately conducted tests - it is about observations. For example, one can make observations about stellar evolution, but one cannot set up a test.