I've never encountered a Chinese buffet let alone the seafood delight, so I googled around a bit to see what I could learn. I looked at a lot of recipes and they were all disgusting--not the kind of thing I think you'd find in even a bad restaurant. I don't know what you're specifically looking for since you can't already identify it, but what I did learn is that this dish is often made with cream, which carries flavor very well. A small amount of cream will only add a small amount of fat.

The most common Chinese spice blend in the U.S. is Chinese Five Spice, but that may not be what you're looking for at all. In fact, since this is really an American recipe, it might just be Old Bay. Both are reddish, which didn't appear in the pictures I saw, however.

You can make mushroom sauce fairly easily with either fresh or dried mushrooms (look it up and you'll find plenty of recipes). Some of the recipes I saw just use cream of mushroom soup, but you get out of it what you put in it, and fresh is so much better.

If no one has a better answer for you, try asking people who cook in restaurants with the food you're trying to replicate, or even at a restaurant itself. If you're friendly and just say something casual like, "This is so good! What's in it?" they might tell you.

Items to purchase: Chinese Wine, or substitute dry sherry. I recommend dry sherry.

Fish Stock, or substitute Knorr Fish Cubes or many of the brands of Japanese dashi mix

Toasted Sesame Seed Oil

Rice Wine Vinegar, or Rice Vinegar. Vinegar has different tastes, rice wine vinegar may be softer, not as much bite as rice vinegar, and may have a subtle taste difference. Rice Vinegar is softer, not as much bite than Heinz White Vinegar.

Soy Sauce, fresh ginger, fresh garlic, fresh green onion.

Cornstarch, salt, pepper, sugar.

If you like seafood delight, have you tried chicken with mushrooms?

Where are your restaurants located? China is a very large country, usually seafood is regional, but in the US, fake crab is available away from the "sea"

I've had Seafood Delight at Chinese buffets around here and I've searched several times for a recipe like it but haven't found one (just searched again on-line and through my Chinese cookbooks for anything similar). The Seafood Delight here is often made with shrimp, [fake] crab, pea pods, and sometimes mushrooms. I think it's a simple white sauce w/ minimal seasonings made with a basic stock -- probably chicken, but you could use veg stock -- perhaps amped up w/ a little dry sherry and maybe a little fish sauce or oyster sauce (depends on how flavorful your seafood is)... maybe garlic, but I'd go light-handed to start. I'm not convinced there's much more in it... could be a splash of light soy sauce, but not enough to darken an otherwise white sauce. I don't detect egg, ginger, onions, or any of the usual suspects.

ETA: IOW, if I were to try your variation, I'd get a hot wok, add a bit of veg oil, add 1 clove minced garlic (haha!), saute one min., then add fake crab and mushrooms as req'd to cook through or heat fully (i.e., mushrooms first if they're raw, because I'd want to handle the fake crab as little as possible). I'd add a splash of dry sherry (like 1 tbs to deglaze), then I'd add a slurry made from chicken/veg stock and cornstarch and simmer/stir to thicken.... maybe also w/ some fish sauce since you're only using fake crab, and I'd probably also add a splash of light soy sauce. lol! At least that's where I'd start -- and then I'd figure out where it needed to go from there.

The major common final flavor of a Chinese mixed seafood dish is a result of the following:

Ginger + garlic + scallions + sesame oil + soy sauce + MSG + nuclear hot wok

dcarch

dcarch, I did suspect MSG, but I've never used it. Do you?!

I don't use msg but I've always assumed every Asian buffet, and at least all over the South, they have all been almost identical in the flavor and food, every little town has at least one, my little rural town has 6, that msg was the main special ingredient outside of the usual list dcarch mentions. Tasty but not healthy.

I use the ingredient combination that dcarch listed, except that I use chili sauce instead of MSG.