To beign with going through ICN has two MAJOR problems:
1) your ticket will be double at least than going QF meta, AA codeshare from the US.
2) the cheapest class the offer is Q, and it doesnt count for EQMs, nor RDMs.
Therefore forget about using KE.

The best and cheapest way (which Im doing this thursday, not intentionally)
Is to go via SIN or BKK (usually SIN from the east coast). This is what im doing which in coach would have been a few hundred bucks less than using QF/NZ/UA/TN, but Im on a J ticket and its not for MR purposes as I NEED to stop by SIN both ways.
4/5:
BOS-NW-MSP-NW-NRT-NW-SIN-QF-SYD-QF-OOL/BNE-QF-MEL-QF-SYD-QF-SIN-NW-NRT-NW-MSP-NW-BOS.

The above itin in Y would have been cheaper than BOS-LAX/SFO-SYD on any carrier for example.