I write this not to point out a mistake, but point out how differently a professional chef looks at food and food problems than a good home cook.
Sushi's good. Fish and chips are good. Reading is very good. First rule of exam taking: Read the question. The way Wacook presented it, was: One fish. One fruit. Two sauces (we infer each should compliment both fish and fruit). One side dish (we infer the same).
You're thinking like a diner and not like a chef. Especially not like a chef-student or chef-teacher. Spicy tuna roll's been done to death -- and there's not much interesting left to "say" about it -- or any other conceivable maki, for that matter. Hamachi's out of season, so are soft-shells. "Barbecued" eel (unagi) comes in a plastic bag already filleted, boned and smoked. Even chefs buy it in the bag, because it's so difficult to bone. FWIW, anago can be easily purchased boned, frozen and raw.
Another thing about your sushi suggestion is preparing and having ready sushi quality rice. It certainly adds another dimension, and a very subtle one. Could be a good one.
Sushi quality tuna seems like it may be enduring as an ingredient in several different style preparations, mostly beginning with something tataki-esque. OTOH, it's a trend whose time may have run. I'm not close enough to wacook's school or region to know. FWIW, the big "seasons" for northern-hemisphere blue-fin tuna is winter; for southern, summer. We're at the end of the season for the best fish. Good tuna's not exactly seasonal though. It's a fish-by-fish basis for suppliers, they're caught when they're caught.
The rule in food since the nouvelle revolution, for more than forty years, has been to present fresh seasonal foods, local if possible. It's important wacook, as a student, show sensitivity to this rule. As a practical matter this means going to the fish market at least once, then at least phoning them a few times during the week before the exam to find out what's fresh and in good supply. It also means having a "plan B" if her preferred fish isn't in stock at the quality she demands.
You can apply this lesson to your career as a sushi eater -- remember to always ask the chef what's freshest and best. They enjoy designing your meal a lot more than they like being told to make the same rolls over and over. Trust me. You'll be rewarded on the plate.
It's also a good idea for a student to show some appreciation of the prep, cooking and plating techniques she's learned in school. I.e., "kissing-up." With an assignment such as Wacook's this could mean "splitting the baby," by keeping half the dish in-the-box and spreading her wings on the other half. For instance, one thing Wacook might take from your suggestion is a cold wasabi flavored sauce made with creme fraiche -- sourced from a Mexican restaurant as crema fresca (high-quality, delicious, fresh, inexpensive, locally made -- that's thinking like a chef). Running with your idea a little farther, she might consider using a sauce like that with a lightly grilled hirame-engawa (halibut fin-muscle) with lychee in a temaki (ice-cream cone shaped hand roll) presentation.
Simple but perfect is a risky strategy. Certainly you want a restaurant menu to reflect that aesthetic -- mostly. However, school is not a restaurant. The problems with "fish and chips" are saucing and a too-simple preparation to impress the teachers. It's also low-brow and juvenile. Fried. I like it, you like it, they like it. It won't grade well, though.
Q: "What are these two sauces?"
A: "Malt vinegar and tartar."
Q: "What do you plan to do when you grow up?"
Again, not to say that it isn't a good idea for dinner. Ten years ago, I had to go to London for a week on a heavily subsidized business trip and was able to bring my family with me. My then teen-aged son ordered fish and chips at Bibendum, and they, by God, made a great plate of fish and chips. Not to be outdone, the next night my septuagenarian dad ordered fish and chips at Simpson's in the Strand. Just as good. But I digress.
A chef analyzes food across a lot of different axes. Among them: wow factor, price to get on the plate, price which can be charged, availability of ingredients, quality of ingredients, seasonality of ingredients, the nature of the clientèle, adaptability with other dishes on the menu, etc. Being a chef is a lot more than getting good food on the plate. Wacook's not only being graded on how she cooks, but how she thinks. Not like a diner, like a chef.