i dont know alot about geese,,, but roosters are just as mean,,,and you can teach them to get along,,, if you (and you should) get chicks,,then always let the kids interact with them,,they should get along fine,,,they usually know who's suppose to be there,,and "who" or "what" is not.
like dogs,,,they all can be trained,,,just sometimes you get that dog that just dont like kids.