i've taken this flight in F several times. Normally I board and have a full dinner. Then sleep til about 2 hours or so prior to landing and have breakfast. It's long enough so you can do that.
I'll second what ironmanjt says - ey's catering really isn't that amazing. It's gone way downhill in the past year or so.
with such a long layover in AUH I'd recommend going and seeing the mosque and having dinner in town somewhere. If you like Middle Eastern/ lebanese food a great high end option is Sambusek at the Rosewood hotel - my favorite. for a cheaper and fun Middle Eastern / Lebanese option Lebanese Flower near al Wahda mall is an absolute classic. Let me know if you have other questions or need recs.