I've actually tried this before, they won't let you into the F lounge at NRT. I even tried to convince the OZ staff at check-in to give me an invite card at NRT since it's an F ticket but they just said to use the F lounge in ICN and the C lounge at NRT. Unfortunately the F lounge is ICN is severely underwhelming.
As puchong mentioned above, the ANA F lounge is also not one of the better in the world but they do offer Hibiki 21 if you're into high end whisky and they have a small menu to order from if you're hungry. The C lounge only has the noodle bar, which I'm not a fan of, and a few other items on the buffet.