KE is an excellent airline, including in economy. Have not tried their A380 yet but I'm sure it is even better as it is a great plane (flown it with other airlines). ICN is also an excellent airport to transit at, compact and easily useable with plenty of retail and food options, and should you have too long a connection, there is an airside transit hotel which rents out rooms for a few hours so that the kids can have a nap and your wife and yourself a bit of rest or a shower. I would thoroughly recommend that itinerary.