No car. Big group. Range of abilities, but none of them expert/high advanced. Not able/not willing to hire and use car. You want to go to Niseko. Your point about the lifts being faster is moot, who cares? They are mostly gondolas or detachables anyway, it's not an issue. Do you realise that driving from Cortina (northern end of Hakuba) to Goryu (southern end of Hakuba) takes over 30mins most days? And the shuttle buses wont be any quicker. Niseko is going to suit your group a lot more.