Storage: either bake immediately once assembled OR freeze immediately raw then deep fry/bake from frozen, (15 mins for baking). Cooked fish fingers don't keep that well because crumb goes soggy and because they are so small, they don't reheat well in the oven (inside tends to dry out).
Baking: Preheat oevn to 220°C / 425°F. Spray tray with oil.