For us to have reached the stage 2 target all that was needed was for 60k players to donate 25k balloons each. (1,500,000,000/25,000). I managed to do that on Newfoundland, Sandycove, Northisle and even Zeus where I am only level 40 and until this event only had 4 tavern generals to do adventures with. This suggests to me that the player base has to be well under that 60k number, across the whole world....Or maybe we have a much bigger base and many haven't been converting anything and waiting for others to reach the global target?
The achievements need to be adjusted to reflect how many balloons you donate and that is where the gifts should be. After all, you can easily have a cake dropped onto an inactive festival hall 10 times to manage those achievements.