I don't know much about taekwondo. But it looks like the weight is mostly on the back foot. That is different from most aikido.
not quite. their weight is on both feet. they trained to kick with either foot from any position. so for TKD, they balanced on both feet. they tend to bounce up and down on both feet so they can switch their feet in mid-air and kick you with either foot or both feet at the same time.