we're also going this Oct to Bali and most likely thru ICN same way w/FF miles to DPS.

I would never want to chance OAL on zed/ID90 for the long haul--you'll probably get coach. I guess it all depends on your seniority and point of view and flexibility. I'd take a look at dates for special events in the connecting cities as well as BKK before I starting planning. Consider--iffy standby when it's full moon party time in Thailand--or the biggest trade show weeks in Seoul, cherry blossom time in Japan...
There's also that issue of red-eyes and bizarre connection times in Asia. That can mean at least one more overnight in a city.