All else being equal - that is, the child is developing well, has a stable family situation, is healthy - children are quite adaptive and tend to fine with moves after an inital adjustment. As they say, 'the devil is in the details', and there may be other issues involved with your friend in addition to any concerns about the wellbeing of the little girl.
It is easier for one to move than two. Also, Alberta has far more job opportunities than Ontario. Is there any reason why you cannot move to the west?