Thanks for the advice, especially on arriving at the airport early! I had some dreadful arrival immigration lines at ICN post-Covid, and have thus avoided overnight/landside connections when possible. I've been somewhat lucky on departure with waits of 20-30 minutes at T2, but the crowds throughout the airport were pretty significant and ICN doesn't seem to be too eager to expedite business/status passengers through security and immigration.

If I have to be at ICN around 6am for a 9am flight, that would mean departing from central Seoul around 4:30am. My airline (AF) doesn't participate in City Airport Terminal check-in (where one can complete immigration formalities at the station and then use the diplomat lane at ICN), otherwise I'd check in there and take the first train (arriving ICN T2 at 7am).

If I transfer to GH ICN the night before, gotta budget 2 hours for that, and then still have the 20ish minutes shuttle to T2 on the departure morning. Doesn't sound that tempting either. I'm gonna lock in the PH/GH ICN option for now -- would like to see the PH again (I think it might have been Cat 4 when I last stayed there), and at ~$700/night it certainly is a decent way to blow a Cat 1-7 cert.