I was several times on Connection through BKK with layover more then 12 hours and overnight. I had never any Problem with my luggage.
Problem will be that in ICN they will probably not check through your luggage as time to departure is more then 24 hours. check in people in ICN are quite strict and not with the usual "TG flexibility". you might Need the help of the Supervisor, but there is still some probability, that they do not check it through