1. Who came from the planet Wexr II?
The Superboy (and later Superman) Revenge Squad originated on that planet.
2. Who came from the planet Staryl?
Luma Lynai, an adult version of Supergirl hailed from Staryl:
3. What was the name of the hover-car that Jor-El invented?
Jor-El invented the Jor-El (the guy wasn't too vain). I presume it was a cousin of Jor's who invented the Eds-El.
4. Who lived on the planet Htrae?
Htrae was the Bizarro world.
5. Why was Jax-Ur sentenced to the Phantom Zone?
Jax-Ur destroyed an inhabited moon of Krypton.
Jim got #2, #4, and #5 right. Michael Rebain got all five on the button. David apparently knew all five and contributed the additional information that the inhabited moon was named Wegthor. Jacque Nodell also got all five correct. Great job by all!