The problem is that "A" inventory is used both for paid "discount" F (like D > A with RTWs) and as upgrade inventory for pax using SWUs or miles. Because DFW-ANC and v.v. is so grueling in coach on a 757, anybody who knows anything works like hell to get upgraded, so AA is very reluctant to release A inventory too early.

A phone call to the AA RTW desk might break it loose, (not great odds but some) or else the OP could get ticketed for an acceptable itinerary, then pay $125 to re-issue when and if A inventory to/from ANC opens.

This is why I recommended the OP consider breaking the trip at HNL, flying in A for a 180 TP run to the mainland, then saving the transcon for a 180 TP segment later, vs. LAX-YYZ which doesn't offer A but only D as a Canadian destination.