Some advice for during the competition because they will be watching...
Keep your station clean, tools that you use a lot but aren't currently using in a bucket of sanitizer, i.e. your chef knife. Use tasting spoons, never your finger or the spoon you're using to stir it (automatic disqualification in a lot of ACF comps).
Can you get lamb livers or sweet breads? Nearly any other cuts of lamb (other than the loin) will require a long cook time. Not always but usually. Pressure cookers can help and using a recipe with small pieces can help breakdown the chewiness.
Lamb can be overplayed but nearly any food in a food comp is. It is hard to be original when new species of game aren't really popping up out of the forest.
If you can make a cheap cut of meat taste great that can go far but presentation and flavor will be top points.