They cannot be sweetgum, as sweetgum's leaves are alternately arranged on the stem. The last two pics could be maple, too, but not the same as the others. At such a young age, these last two could be many different species, but my guess would be Amur maple (Acer ginnala) since this is a wide spread, often weedy tree in the east and midwest U.S.
The first and third (and probably the second) pics are most likely Sugar or Norway maples (and they tend to be the most commonly planted), but too early to tell positively. Keep in mind that different maple species often (or usually) cross pollinate, and intermediaries result. Your best guess will be determined by the nearby mature trees.
