With Superboy, you could go back to the 1945 version, where leaping over a barn or outrunning a deer were amazing feats. He was weaker than the 1938 version of his adult self. Even the world's greatest superhero has to begin somewhere...
The Smallville TV version is a more modern (and powerful) take.
I thought about the Marvel family, but omitted them to keep things short. Still, Captain Marvel, Captain Marvel Jnr and Mary Marvel are all potential teen heroes.
I skipped the Legion, because they are such radical outliers. Still, there were enough stories where individual members came back in time and did things, that they could be used as a source. In the first appearance of Ultra Boy, he only had (used?) his vision powers. His full power set wasn't mentioned until his second(?) appearance. The result was Cyclops with X-ray and telescopic vision. (And a flight gizmo, because the Legion.) Perfectly fine.