I spoke to Qantas and confirmed a couple of things that had been the subject of discussion across various threads in this forum.

1) The rules for ex-CAI RTWs aren't any different than any other RTWs. (The idea that they're being treated as a "mistake fare" is inaccurate.) The prior rules apply. This shouldn't be a surprise, and you may need to HUCB with Qantas to get an agent who honors it appropriately, but there should be nothing for Qantas to stand on here in terms of treating these fares differently.

2) The cancellation fee is 5% of the base fare without taxes.