Hello dear,i have travelled with KLM couple of times.From my experience,you dont need any airport shuttle when you arrive schipol.it is very big airport but you ll be alright.The distance again depends on your gate,am sure there ll be sufficient layover time to get to your gate n even window shop,lol.And incase you re with kids n your waiting time is much,there is mc donalds somewhere at the upper floor,just ask the airport attedants.
For the excess luggage,i dont have experience on that but if you log in to their site using your Ref.no,you ll find something useful on your itinerary.