This all requires Napoleon to win the battles in the lowlands and then to give the allies another thrashing. If he won the first group of battles the morale of the French army would be quite high and the French army of 1815 was a very motiviated one. Still it is a what if position and I am supposing that the Austrians could be motivated that it was in their self interest to leave the coliation and perhaps even support France. This would have left the Czar to withdraw from Europe and even the Prussian might have retired. Everyone was becoming war weary .