Lol, in response to your first question, I confess that didn't even consider birds or flying creatures at all. But now you mention it, I guess it would only be fitting for me to add them in. I'll get on to that as soon as I can haha!

In regards to social structure and government, Social tiers differ within each tower but there is a general rule that the higher the level you live on, the higher your status.
And the World Navy takes primary charge over all of the towers and the Wandering Islands but they have installed Governing Officers which are essentially just your usual Governors. Although I'm considering a female empress character for the Pyramid tower.

As for powers go, I wanted to give you guys the benefit of the doubt to see what you could come up with and go over it afterward. And having a Shard Power is extremely rare. On top of that, most of those who have powers have gained them via hereditary means. Once the seed is passed on to a fetus, that person loses their power.

There are the exceptions as well, people who have direct exposure to Shard fragments. They are noticeably more powerful than other people with abilities and their power does not pass on, nor do they lose it until the shard is removed from their being. These guys are far and few between.