Again you are demonstrating your unfamiliarity with the territory. Change in a population does indeed occur in populations regardless of selective pressure. That is because many mutations are negligible in their effect. It would be unusual, or very slow for such drift to result in new species, unless a population is split by some barrier.
Again,you are thrashing around, looking for a gotcha. If you were honestly looking for information, you would be reading books by experts that specifically address your questions. You might then ask for clarification.
Instead, when you have been confronted with an actual technical answer, you brush it off and move on to the next question on your list.