MS @UT Austin HCI, UX researcher and designer, mainly on children learning from touchscreen and eye-tracking
I’m curious to learn how you managed to navigate all the constrains in the brief. Oh wait, there wasn’t a brief?
The easiest test to check visual balance is blurring the items. If your icons turn into more or less similar blobs, they have the same optical weight.
Now it’s clear why an icon area is always larger than an icon body — just to allow non-square icons fit it and look not smaller than square icons.