No. The problem with post polio syndrome is not your muscles but your nerves. The primary nerves were destroyed by the virus in your spinal cord. Now the remaining nerves have sprouted new terminals to reconnect these muscles. Moving around will help you to maintain mobility and function. But don't push it too much. Extreme is often a feature of post-polio syndrome. See your doc for more information.
No. I don't see how movement can harm your muscles. Maybe some excessive movement might, but normally muscles are designed to move. Moves stays at the basis of physical therapy, which is a cornerstone treatment for those with post polio syndrome.
No. Srenuous Exercises and over exertion can be harmful but normal movements are not harmful.
Unlikely. Polio affects the muscular anterior spinal fibers causing weakness starting at the lower extremeties and upper and breathing in more severe cases. Post polio is when someone had this effect earlier in life and the weakened fibers sort of lose their capacity and the weakness returns to some degree. Eye muscles originate in the brain and are not subject to this problem.