Here are some further things to consider:
1) I would second (fourth?) the advice to not consider staying overnight in lounges. Not only will they be unlikely to be open at night, some will not even be open during the day time.
2) Because ANC will not be “in season” for AA when you will be traveling, why not take advantage of an AA seasonal flight that will be operating: LAX-SJO (so you could do LAX-SJO-DFW or vice versa). Costa Rica is a great place to visit. Or another winter destination is SJU- which is also a good place to visit as well as being a reasonable round trip (mileage-wise, etc) that operates year-round.
3 Because you seem to like glaciers, fjords, etc. (viz, going to PUQ and wanting to go to ANC), why not consider SCL-AKL and then a separate side trip to the west coast of the South Island of NZ. Doing SCL-AKL-SYD would take an extra segment but you seem to have one or more to spare.
4) Another possibility for the transition from Europe to NA would be to do CAI-LHR-LAX-JFK. This would give some longer haul segments (relevant if a D ticket) and might offer some other possibilities for timing for the other NA segments.
4) And oh, BTW, YVR is an even better place to visit than SEA or PDX. You can do DFW-YVR-DFW (or perhaps even better DFW-YVR-SFO and make your own way SFO-LAX).