Got my adapter from @jassin000. Until I get my Axunworks CF Netdimm, I only have a Slashout cartridge to test with. It's (edit: meaning Slashout) not mentioned as working in the linked thread, and doesn't appear to work on first try. So I'm not sure if Slashout just doesn't support Maple input, if I didn't set it up right, or if there's a hardware issue.
Is there anything I need to do to make the Naomi 2 recognize Maple input, or should I just hang tight until I can test one of the games that's known as working?