Turns out there was more like 10 tiny fillets. I ended up putting the coconut milk into a Pyrex casserole dish type thing, mixing well with salt, pepper, cardamom, ginger, chili, onion, garlic, chili sauce (Sriracha), and lemon juice. Then I put in 3 cups of dry rice just covered with water (like 1mm). I should've layered the fish and rice, but it didn't occur to me until the rice was already in. So I put in a few fillets, mixed it into the rice, then put in the rest. Now baking at 350.

I'm taking the risk of over cooking the fish I guess, but I did want to stay as true as possible to the past creation, which involved exactly 1 cooking dish. All the moisture and fat should keep it from being dry at least, though I honestly know nothing about cooking fish, so hopefully it doesn't get super rubbery or anything.