The line is the umpire's, the foot doesn't have to be grounded but as it lands some part has to be behind the line. I don't think the law has changed. For runs if memory services the batsmen is home as soon as in contact with the line/ popping crease.
Ali bowled less than Malan today. Anyone still for him playing in this test and the next or do you still think it was 'madness' to suggest dropping him?
Unless he scores a big amount of runs or suddenly learns how to bowl properly, and he can't bowl spin properly.. He's got to be dropped for his own good. He'll come back better I'm sure but at the moment is not performing well enough by anyone's standards