To answer some of your ?'s - yes they will grow. Alot of the new polyps will start from pieces of the foot left behind as the larger ones move around. The little ones will grow bigger over time if they are cared for (water quality). They will also move to a spot that suits them. I have had my yuma rics multiply both ways - by splitting and also starting from pieces of the foot as the big one moves
John
"Critics are men who watch a battle from a high place and then come down and shoot the survivors." Ernest Hemingway