Some thoughts on your situation..

1. I tihnk those seats are not fully horizontal. It may be an angle lie flat. However, it'll still do the job. KE does block seats for their Elites, so you may not be able to get anything different up until check in. But if you have an aisle up front, that's probably good enough?

2. The KE lounge that is closest to the immigration I feel is a touch nicer, but can get crowded, especially in the mornings. Prestige Garden West opens at 4am, Garden East at 7am and Prestige East at 6am. Garden lounges can be nice with the outdoor access, but during this winter I don't think many people will be going outside. Not sure how you'll spend 3 hours there!

3. If any meal runs out, it is usually the Korean bibimbap or whatever korean dish they are offering. I wouldn't worry too much if they run out. If you've tried it once, you've tried it. That offering almost never changes. It is good and consistent.

4. If you decided to skip the meal and get sleep instead, I think the flight attendants should be able to serve the other 2 passengers from the other side. The flight is so short, I usually see a good number of passengers skip the meal service and try and get sleep. Sleeping in the plane might be preferred to any spot in the lounge.