To begin with, you should read the guidelines for challenge caches and make sure that there are nothing there that would stop your planned challenge from being published. Surprisingly many people skip this step.
The guidelines are here: https://www.geocaching.com/help/index.php?pg=kb.chapter&id=127&pgid=206
Once you've checked that, there should be no problem with your reviewer (unless you happen to collide with another cache or something like that, but that doesn't have anything to with this being a challenge) and it's also probable (but not certain) that it will be possible to make a checker.
Your next step is to write a message at https://project-gc.com/forum/list?8
to ask the challenge checker volunteers for help creating a checker.