Of course SqD says a C/H breaker is not allowed in their installation instructions but U/L says it is listed for the application. It is a classic "listing" vs "labeling" dispute.
That is why I said you really need to ask the AHJ. That is also why CH has a sticker that you put in the panel so it is "labeled" to accept the CH breaker.
In the meetings I have been in it is always a split decision, sometimes quite vociferously. I have been in the room several times when Harvey Johnson (CH) and Jim Pawley (SqD) have had it out. The funny thing is Jim would end up staying at Harvey's house when he was in town and car pool up to the IAEI meeting.
BTW I have an off the wall (actually "in the wall" I suppose) idea. Extend the 14/3 down into a readily accessible location, mount a little 2 slot panel with 2 AFCIs and go back up to the original J box with a pair of 14/2s or just do the whole thing with some fished smurf and do it all on one raceway with THHN.
210.12 talks about branch circuits, not feeders.
