OK, so that part of what was tripping me up. Seemed that my former assumption was incorrect.
It seems that whatever license you apply a derived product, it ONLY applies to your "original" creation, not anything that is taken from the SRD (also mentioned in the CC FAQ, albeit somewhat hidden -- assuming I'm understanding it correctly). That makes sense!
Still though, this introduces some complications for the CC that were not in the OGL. E.,g. if you change something significantly, there can be ambiguity in what is considered original and what is considered "the source." Although perhaps in practice this is not a big deal. Similarly, since you don't have to enumerate what is and isn't taken from the SRD, the burden of that is left on future adapters of your derivative work to comb through the text should they want to make that distinction. Then again, I can't imagine many scenarios where that would be necessary.