Hello fellow Atlantan.
Just did this with friends. Booked the 2 of them on ANZ in biz ORD-LAX-SYD, and me on UA in F ATL-SFO-SYD open jaw Seoul-SFO-ORD-ATL
The Biz class (90K) award is only avail. on the nonstop LAX/SYD flight. No connections in the S. Pacific. I assume the Y and F are similar.
To have connections/stopovers (except in LAX, I presume), I think you need to book the more expensive "South Pacific" award level.
It includes UA Coach (Y) class connecting service from continental US. No upgrade to F (like on the UA 90K biz ticket).
Call UAMP, book the seats (takes 24 hours while they are queued to Air New Zealand) then visit the City Tkt Office in B'head (the ladies there are terrific) and get your tix and your electronic visa all at one time.
Finally, I don't think I'd fly the nonstop ATL-LAX (strictly because it's so early) to connect to this unless you spring for a day room at a nearby hotel (I did the UA to UA connx through SFO this spring and it made for a veeery long day.)
Email me w/other questions.
jl